Implement small business inventory system with FastAPI and SQLite

- Set up project structure for FastAPI application - Create database models for items, categories, suppliers, and transactions - Set up Alembic for database migrations - Implement API endpoints for all entities - Add authentication with JWT tokens - Add health check endpoint - Create comprehensive README with documentation
2025-06-12 11:24:38 +00:00 · 2025-06-12 11:24:38 +00:00 · becbb01753
commit becbb01753
parent 3524acfac1
40 changed files with 1662 additions and 2 deletions
--- a/README.md
+++ b/README.md
@ -1,3 +1,141 @@
-# FastAPI Application
+# Small Business Inventory System

-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A comprehensive inventory management system built with FastAPI and SQLite, designed for small businesses.
+
+## Features
+
+- **User Authentication**: Secure login and user management system
+- **Item Management**: Create, read, update, and delete inventory items
+- **Category Management**: Organize items by categories
+- **Supplier Management**: Keep track of item suppliers
+- **Transaction Management**: Record stock movements (in/out/adjustments)
+- **API Documentation**: Interactive API documentation with Swagger UI
+
+## Technology Stack
+
+- **Backend**: FastAPI (Python)
+- **Database**: SQLite with SQLAlchemy ORM
+- **Migration**: Alembic for database migrations
+- **Authentication**: JWT token-based authentication
+- **Documentation**: Swagger UI and ReDoc
+
+## Project Structure
+
+```
+.
+├── app/
+│   ├── api/
+│   │   ├── deps.py           # API dependencies
+│   │   └── v1/               # API v1 endpoints
+│   │       ├── endpoints/    # Individual endpoint modules
+│   │       └── api.py        # API router
+│   ├── core/                 # Core modules
+│   │   ├── config.py         # Settings and configuration
+│   │   └── security.py       # Security utilities
+│   ├── db/                   # Database utilities
+│   │   ├── base.py           # SQLAlchemy declarative base
+│   │   └── session.py        # Database session management
+│   ├── models/               # SQLAlchemy models
+│   └── schemas/              # Pydantic schemas
+├── migrations/               # Alembic migrations
+├── alembic.ini               # Alembic configuration
+├── main.py                   # Application entry point
+└── requirements.txt          # Project dependencies
+```
+
+## Setup and Installation
+
+### Prerequisites
+
+- Python 3.8 or higher
+
+### Installation
+
+1. Clone the repository:
+   ```
+   git clone https://github.com/yourusername/smallbusinessinventorysystem.git
+   cd smallbusinessinventorysystem
+   ```
+
+2. Install dependencies:
+   ```
+   pip install -r requirements.txt
+   ```
+
+3. Set up environment variables:
+   ```
+   # Create a .env file with the following variables (optional)
+   SECRET_KEY=your-secret-key
+   ```
+
+4. Initialize the database:
+   ```
+   alembic upgrade head
+   ```
+
+5. Run the application:
+   ```
+   uvicorn main:app --reload
+   ```
+
+## API Documentation
+
+Once the application is running, you can access:
+
+- Interactive API documentation: [http://localhost:8000/docs](http://localhost:8000/docs)
+- Alternative documentation: [http://localhost:8000/redoc](http://localhost:8000/redoc)
+
+## Environment Variables
+
+| Variable | Description | Default |
+|----------|-------------|---------|
+| PROJECT_NAME | Name of the project | Small Business Inventory System |
+| SECRET_KEY | Secret key for JWT encoding | supersecretkey (change in production!) |
+| ACCESS_TOKEN_EXPIRE_MINUTES | JWT token expiration time | 30 |
+
+## Database
+
+The application uses SQLite as the database, stored at `/app/storage/db/db.sqlite`. This location can be configured through environment variables if needed.
+
+## API Endpoints
+
+### Authentication
+- `POST /api/v1/login/access-token` - Get access token
+
+### Users
+- `GET /api/v1/users/` - List users (admin only)
+- `POST /api/v1/users/` - Create user (admin only)
+- `GET /api/v1/users/me` - Get current user
+- `PUT /api/v1/users/me` - Update current user
+- `GET /api/v1/users/{user_id}` - Get user by ID
+- `PUT /api/v1/users/{user_id}` - Update user (admin only)
+
+### Categories
+- `GET /api/v1/categories/` - List categories
+- `POST /api/v1/categories/` - Create category
+- `GET /api/v1/categories/{category_id}` - Get category by ID
+- `PUT /api/v1/categories/{category_id}` - Update category
+- `DELETE /api/v1/categories/{category_id}` - Delete category
+
+### Suppliers
+- `GET /api/v1/suppliers/` - List suppliers
+- `POST /api/v1/suppliers/` - Create supplier
+- `GET /api/v1/suppliers/{supplier_id}` - Get supplier by ID
+- `PUT /api/v1/suppliers/{supplier_id}` - Update supplier
+- `DELETE /api/v1/suppliers/{supplier_id}` - Delete supplier
+
+### Items
+- `GET /api/v1/items/` - List items
+- `POST /api/v1/items/` - Create item
+- `GET /api/v1/items/{item_id}` - Get item by ID
+- `PUT /api/v1/items/{item_id}` - Update item
+- `DELETE /api/v1/items/{item_id}` - Delete item
+
+### Transactions
+- `GET /api/v1/transactions/` - List transactions
+- `POST /api/v1/transactions/` - Create transaction
+- `GET /api/v1/transactions/{transaction_id}` - Get transaction by ID
+
+## Health Check
+- `GET /health` - Check system health
+- `GET /` - Basic service information
--- a/alembic.ini
+++ b/alembic.ini
@ -0,0 +1,74 @@
+# A generic, single database configuration.
+
+[alembic]
+# path to migration scripts
+script_location = migrations
+
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# timezone to use when rendering the date
+# within the migration file as well as the filename.
+# string value is passed to dateutil.tz.gettz()
+# leave blank for localtime
+# timezone =
+
+# max length of characters to apply to the
+# "slug" field
+# truncate_slug_length = 40
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+# set to 'true' to allow .pyc and .pyo files without
+# a source .py file to be detected as revisions in the
+# versions/ directory
+# sourceless = false
+
+# version location specification; this defaults
+# to alembic/versions.  When using multiple version
+# directories, initial revisions must be specified with --version-path
+# version_locations = %(here)s/bar %(here)s/bat alembic/versions
+
+# the output encoding used when revision files
+# are written from script.py.mako
+# output_encoding = utf-8
+
+# SQLite database URL
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S
--- a/app/init.py
+++ b/app/init.py
--- a/app/api/init.py
+++ b/app/api/init.py
--- a/app/api/deps.py
+++ b/app/api/deps.py
@ -0,0 +1,62 @@
+from fastapi import Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordBearer
+from jose import jwt, JWTError
+from pydantic import ValidationError
+from sqlalchemy.orm import Session
+
+from app.db.session import get_db
+from app.models.user import User
+from app.core.config import settings
+from app.schemas.token import TokenPayload
+
+oauth2_scheme = OAuth2PasswordBearer(
+    tokenUrl=f"{settings.API_V1_STR}/login/access-token"
+)
+
+
+def get_current_user(
+    db: Session = Depends(get_db), token: str = Depends(oauth2_scheme)
+) -> User:
+    """
+    Validate and decode token to get current user.
+    """
+    try:
+        payload = jwt.decode(
+            token, settings.SECRET_KEY, algorithms=[settings.ALGORITHM]
+        )
+        token_data = TokenPayload(**payload)
+    except (JWTError, ValidationError):
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="Could not validate credentials",
+        )
+    user = db.query(User).filter(User.id == token_data.sub).first()
+    if not user:
+        raise HTTPException(status_code=404, detail="User not found")
+    if not user.is_active:
+        raise HTTPException(status_code=400, detail="Inactive user")
+    return user
+
+
+def get_current_active_user(
+    current_user: User = Depends(get_current_user),
+) -> User:
+    """
+    Get current active user.
+    """
+    if not current_user.is_active:
+        raise HTTPException(status_code=400, detail="Inactive user")
+    return current_user
+
+
+def get_current_active_superuser(
+    current_user: User = Depends(get_current_user),
+) -> User:
+    """
+    Get current active superuser.
+    """
+    if not current_user.is_superuser:
+        raise HTTPException(
+            status_code=403, detail="The user doesn't have enough privileges"
+        )
+    return current_user
--- a/app/api/v1/init.py
+++ b/app/api/v1/init.py
--- a/app/api/v1/api.py
+++ b/app/api/v1/api.py
@ -0,0 +1,11 @@
+from fastapi import APIRouter
+
+from app.api.v1.endpoints import items, categories, suppliers, transactions, login, users
+
+api_router = APIRouter()
+api_router.include_router(login.router, tags=["login"])
+api_router.include_router(users.router, prefix="/users", tags=["users"])
+api_router.include_router(items.router, prefix="/items", tags=["items"])
+api_router.include_router(categories.router, prefix="/categories", tags=["categories"])
+api_router.include_router(suppliers.router, prefix="/suppliers", tags=["suppliers"])
+api_router.include_router(transactions.router, prefix="/transactions", tags=["transactions"])
--- a/app/api/v1/endpoints/init.py
+++ b/app/api/v1/endpoints/init.py
--- a/app/api/v1/endpoints/categories.py
+++ b/app/api/v1/endpoints/categories.py
@ -0,0 +1,110 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_current_active_user, get_db
+from app.models.category import Category
+from app.models.user import User
+from app.schemas.category import Category as CategorySchema, CategoryCreate, CategoryUpdate
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[CategorySchema])
+def read_categories(
+    db: Session = Depends(get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Retrieve categories.
+    """
+    categories = db.query(Category).offset(skip).limit(limit).all()
+    return categories
+
+
+@router.post("/", response_model=CategorySchema)
+def create_category(
+    *,
+    db: Session = Depends(get_db),
+    category_in: CategoryCreate,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Create new category.
+    """
+    category = Category(**category_in.dict())
+    db.add(category)
+    db.commit()
+    db.refresh(category)
+    return category
+
+
+@router.put("/{category_id}", response_model=CategorySchema)
+def update_category(
+    *,
+    db: Session = Depends(get_db),
+    category_id: int,
+    category_in: CategoryUpdate,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Update a category.
+    """
+    category = db.query(Category).filter(Category.id == category_id).first()
+    if not category:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Category not found",
+        )
+    
+    update_data = category_in.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(category, field, value)
+    
+    db.add(category)
+    db.commit()
+    db.refresh(category)
+    return category
+
+
+@router.get("/{category_id}", response_model=CategorySchema)
+def read_category(
+    *,
+    db: Session = Depends(get_db),
+    category_id: int,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Get category by ID.
+    """
+    category = db.query(Category).filter(Category.id == category_id).first()
+    if not category:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Category not found",
+        )
+    return category
+
+
+@router.delete("/{category_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_category(
+    *,
+    db: Session = Depends(get_db),
+    category_id: int,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Delete a category.
+    """
+    category = db.query(Category).filter(Category.id == category_id).first()
+    if not category:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Category not found",
+        )
+    db.delete(category)
+    db.commit()
+    return None
--- a/app/api/v1/endpoints/items.py
+++ b/app/api/v1/endpoints/items.py
@ -0,0 +1,126 @@
+from typing import Any, List, Optional
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_current_active_user, get_db
+from app.models.item import Item
+from app.models.user import User
+from app.schemas.item import Item as ItemSchema, ItemCreate, ItemUpdate
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[ItemSchema])
+def read_items(
+    db: Session = Depends(get_db),
+    skip: int = 0,
+    limit: int = 100,
+    category_id: Optional[int] = None,
+    supplier_id: Optional[int] = None,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Retrieve inventory items.
+    """
+    query = db.query(Item)
+    
+    # Filter by owner
+    query = query.filter(Item.owner_id == current_user.id)
+    
+    # Apply additional filters if provided
+    if category_id:
+        query = query.filter(Item.category_id == category_id)
+    if supplier_id:
+        query = query.filter(Item.supplier_id == supplier_id)
+    
+    items = query.offset(skip).limit(limit).all()
+    return items
+
+
+@router.post("/", response_model=ItemSchema)
+def create_item(
+    *,
+    db: Session = Depends(get_db),
+    item_in: ItemCreate,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Create new item.
+    """
+    item = Item(
+        **item_in.dict(),
+        owner_id=current_user.id
+    )
+    db.add(item)
+    db.commit()
+    db.refresh(item)
+    return item
+
+
+@router.put("/{item_id}", response_model=ItemSchema)
+def update_item(
+    *,
+    db: Session = Depends(get_db),
+    item_id: int,
+    item_in: ItemUpdate,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Update an item.
+    """
+    item = db.query(Item).filter(Item.id == item_id, Item.owner_id == current_user.id).first()
+    if not item:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Item not found",
+        )
+    
+    update_data = item_in.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(item, field, value)
+    
+    db.add(item)
+    db.commit()
+    db.refresh(item)
+    return item
+
+
+@router.get("/{item_id}", response_model=ItemSchema)
+def read_item(
+    *,
+    db: Session = Depends(get_db),
+    item_id: int,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Get item by ID.
+    """
+    item = db.query(Item).filter(Item.id == item_id, Item.owner_id == current_user.id).first()
+    if not item:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Item not found",
+        )
+    return item
+
+
+@router.delete("/{item_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_item(
+    *,
+    db: Session = Depends(get_db),
+    item_id: int,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Delete an item.
+    """
+    item = db.query(Item).filter(Item.id == item_id, Item.owner_id == current_user.id).first()
+    if not item:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Item not found",
+        )
+    db.delete(item)
+    db.commit()
+    return None
--- a/app/api/v1/endpoints/login.py
+++ b/app/api/v1/endpoints/login.py
@ -0,0 +1,40 @@
+from datetime import timedelta
+from typing import Any
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordRequestForm
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_db
+from app.core.config import settings
+from app.core.security import create_access_token, verify_password
+from app.schemas.token import Token
+from app.models.user import User
+
+router = APIRouter()
+
+
+@router.post("/login/access-token", response_model=Token)
+def login_access_token(
+    db: Session = Depends(get_db), form_data: OAuth2PasswordRequestForm = Depends()
+) -> Any:
+    """
+    OAuth2 compatible token login, get an access token for future requests
+    """
+    user = db.query(User).filter(User.email == form_data.username).first()
+    if not user or not verify_password(form_data.password, user.hashed_password):
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail="Incorrect email or password",
+        )
+    if not user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST, detail="Inactive user"
+        )
+    access_token_expires = timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
+    return {
+        "access_token": create_access_token(
+            user.id, expires_delta=access_token_expires
+        ),
+        "token_type": "bearer",
+    }
--- a/app/api/v1/endpoints/suppliers.py
+++ b/app/api/v1/endpoints/suppliers.py
@ -0,0 +1,110 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_current_active_user, get_db
+from app.models.supplier import Supplier
+from app.models.user import User
+from app.schemas.supplier import Supplier as SupplierSchema, SupplierCreate, SupplierUpdate
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[SupplierSchema])
+def read_suppliers(
+    db: Session = Depends(get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Retrieve suppliers.
+    """
+    suppliers = db.query(Supplier).offset(skip).limit(limit).all()
+    return suppliers
+
+
+@router.post("/", response_model=SupplierSchema)
+def create_supplier(
+    *,
+    db: Session = Depends(get_db),
+    supplier_in: SupplierCreate,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Create new supplier.
+    """
+    supplier = Supplier(**supplier_in.dict())
+    db.add(supplier)
+    db.commit()
+    db.refresh(supplier)
+    return supplier
+
+
+@router.put("/{supplier_id}", response_model=SupplierSchema)
+def update_supplier(
+    *,
+    db: Session = Depends(get_db),
+    supplier_id: int,
+    supplier_in: SupplierUpdate,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Update a supplier.
+    """
+    supplier = db.query(Supplier).filter(Supplier.id == supplier_id).first()
+    if not supplier:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Supplier not found",
+        )
+    
+    update_data = supplier_in.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(supplier, field, value)
+    
+    db.add(supplier)
+    db.commit()
+    db.refresh(supplier)
+    return supplier
+
+
+@router.get("/{supplier_id}", response_model=SupplierSchema)
+def read_supplier(
+    *,
+    db: Session = Depends(get_db),
+    supplier_id: int,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Get supplier by ID.
+    """
+    supplier = db.query(Supplier).filter(Supplier.id == supplier_id).first()
+    if not supplier:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Supplier not found",
+        )
+    return supplier
+
+
+@router.delete("/{supplier_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
+def delete_supplier(
+    *,
+    db: Session = Depends(get_db),
+    supplier_id: int,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Delete a supplier.
+    """
+    supplier = db.query(Supplier).filter(Supplier.id == supplier_id).first()
+    if not supplier:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Supplier not found",
+        )
+    db.delete(supplier)
+    db.commit()
+    return None
--- a/app/api/v1/endpoints/transactions.py
+++ b/app/api/v1/endpoints/transactions.py
@ -0,0 +1,107 @@
+from typing import Any, List, Optional
+
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_current_active_user, get_db
+from app.models.transaction import Transaction, TransactionType
+from app.models.item import Item
+from app.models.user import User
+from app.schemas.transaction import Transaction as TransactionSchema, TransactionCreate
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[TransactionSchema])
+def read_transactions(
+    db: Session = Depends(get_db),
+    skip: int = 0,
+    limit: int = 100,
+    item_id: Optional[int] = None,
+    transaction_type: Optional[TransactionType] = None,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Retrieve transactions.
+    """
+    query = db.query(Transaction).filter(Transaction.user_id == current_user.id)
+    
+    if item_id:
+        query = query.filter(Transaction.item_id == item_id)
+    if transaction_type:
+        query = query.filter(Transaction.transaction_type == transaction_type)
+        
+    transactions = query.order_by(Transaction.created_at.desc()).offset(skip).limit(limit).all()
+    return transactions
+
+
+@router.post("/", response_model=TransactionSchema)
+def create_transaction(
+    *,
+    db: Session = Depends(get_db),
+    transaction_in: TransactionCreate,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Create new transaction and update item quantity.
+    """
+    # Check if item exists
+    item = db.query(Item).filter(
+        Item.id == transaction_in.item_id,
+        Item.owner_id == current_user.id
+    ).first()
+    
+    if not item:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Item not found",
+        )
+    
+    # Update item quantity based on transaction type
+    if transaction_in.transaction_type == TransactionType.STOCK_IN:
+        item.quantity += transaction_in.quantity
+    elif transaction_in.transaction_type == TransactionType.STOCK_OUT:
+        if item.quantity < transaction_in.quantity:
+            raise HTTPException(
+                status_code=status.HTTP_400_BAD_REQUEST,
+                detail="Not enough stock available",
+            )
+        item.quantity -= transaction_in.quantity
+    elif transaction_in.transaction_type == TransactionType.ADJUSTMENT:
+        item.quantity = transaction_in.quantity
+    
+    # Create transaction record
+    transaction = Transaction(
+        **transaction_in.dict(),
+        user_id=current_user.id
+    )
+    
+    db.add(transaction)
+    db.add(item)
+    db.commit()
+    db.refresh(transaction)
+    
+    return transaction
+
+
+@router.get("/{transaction_id}", response_model=TransactionSchema)
+def read_transaction(
+    *,
+    db: Session = Depends(get_db),
+    transaction_id: int,
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Get transaction by ID.
+    """
+    transaction = db.query(Transaction).filter(
+        Transaction.id == transaction_id,
+        Transaction.user_id == current_user.id
+    ).first()
+    
+    if not transaction:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Transaction not found",
+        )
+    return transaction
--- a/app/api/v1/endpoints/users.py
+++ b/app/api/v1/endpoints/users.py
@ -0,0 +1,154 @@
+from typing import Any, List
+
+from fastapi import APIRouter, Body, Depends, HTTPException, status
+from fastapi.encoders import jsonable_encoder
+from pydantic import EmailStr
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_current_active_superuser, get_current_active_user, get_db
+from app.core.security import get_password_hash
+from app.models.user import User
+from app.schemas.user import User as UserSchema, UserCreate, UserUpdate
+
+router = APIRouter()
+
+
+@router.get("/", response_model=List[UserSchema])
+def read_users(
+    db: Session = Depends(get_db),
+    skip: int = 0,
+    limit: int = 100,
+    current_user: User = Depends(get_current_active_superuser),
+) -> Any:
+    """
+    Retrieve users.
+    """
+    users = db.query(User).offset(skip).limit(limit).all()
+    return users
+
+
+@router.post("/", response_model=UserSchema)
+def create_user(
+    *,
+    db: Session = Depends(get_db),
+    user_in: UserCreate,
+    current_user: User = Depends(get_current_active_superuser),
+) -> Any:
+    """
+    Create new user.
+    """
+    user = db.query(User).filter(User.email == user_in.email).first()
+    if user:
+        raise HTTPException(
+            status_code=400,
+            detail="The user with this email already exists in the system.",
+        )
+    user = User(
+        email=user_in.email,
+        hashed_password=get_password_hash(user_in.password),
+        full_name=user_in.full_name,
+        is_superuser=user_in.is_superuser,
+        is_active=user_in.is_active,
+    )
+    db.add(user)
+    db.commit()
+    db.refresh(user)
+    return user
+
+
+@router.put("/me", response_model=UserSchema)
+def update_user_me(
+    *,
+    db: Session = Depends(get_db),
+    password: str = Body(None),
+    full_name: str = Body(None),
+    email: EmailStr = Body(None),
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Update own user.
+    """
+    current_user_data = jsonable_encoder(current_user)
+    user_in = UserUpdate(**current_user_data)
+    if password is not None:
+        user_in.password = password
+    if full_name is not None:
+        user_in.full_name = full_name
+    if email is not None:
+        user_in.email = email
+    user = current_user
+    if password is not None:
+        user.hashed_password = get_password_hash(password)
+    if full_name is not None:
+        user.full_name = full_name
+    if email is not None:
+        user.email = email
+    db.add(user)
+    db.commit()
+    db.refresh(user)
+    return user
+
+
+@router.get("/me", response_model=UserSchema)
+def read_user_me(
+    current_user: User = Depends(get_current_active_user),
+) -> Any:
+    """
+    Get current user.
+    """
+    return current_user
+
+
+@router.get("/{user_id}", response_model=UserSchema)
+def read_user_by_id(
+    user_id: int,
+    current_user: User = Depends(get_current_active_user),
+    db: Session = Depends(get_db),
+) -> Any:
+    """
+    Get a specific user by id.
+    """
+    user = db.query(User).filter(User.id == user_id).first()
+    if user == current_user:
+        return user
+    if not current_user.is_superuser:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN,
+            detail="The user doesn't have enough privileges",
+        )
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="The user with this id does not exist in the system",
+        )
+    return user
+
+
+@router.put("/{user_id}", response_model=UserSchema)
+def update_user(
+    *,
+    db: Session = Depends(get_db),
+    user_id: int,
+    user_in: UserUpdate,
+    current_user: User = Depends(get_current_active_superuser),
+) -> Any:
+    """
+    Update a user.
+    """
+    user = db.query(User).filter(User.id == user_id).first()
+    if not user:
+        raise HTTPException(
+            status_code=404,
+            detail="The user with this id does not exist in the system",
+        )
+    user_data = jsonable_encoder(user)
+    update_data = user_in.dict(exclude_unset=True)
+    for field in user_data:
+        if field in update_data:
+            setattr(user, field, update_data[field])
+    if user_in.password:
+        user.hashed_password = get_password_hash(user_in.password)
+    db.add(user)
+    db.commit()
+    db.refresh(user)
+    return user
--- a/app/core/init.py
+++ b/app/core/init.py
--- a/app/core/config.py
+++ b/app/core/config.py
@ -0,0 +1,22 @@
+from pydantic_settings import BaseSettings
+from pathlib import Path
+
+
+class Settings(BaseSettings):
+    PROJECT_NAME: str = "Small Business Inventory System"
+    API_V1_STR: str = "/api/v1"
+    
+    # Security
+    SECRET_KEY: str = "supersecretkey"  # Change in production
+    ALGORITHM: str = "HS256"
+    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30
+    
+    # Base directory
+    BASE_DIR: Path = Path(__file__).resolve().parent.parent.parent
+    
+    class Config:
+        env_file = ".env"
+        case_sensitive = True
+
+
+settings = Settings()
--- a/app/core/security.py
+++ b/app/core/security.py
@ -0,0 +1,40 @@
+from datetime import datetime, timedelta
+from typing import Optional, Union, Any
+
+from jose import jwt
+from passlib.context import CryptContext
+
+from app.core.config import settings
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+
+def create_access_token(
+    subject: Union[str, Any], expires_delta: Optional[timedelta] = None
+) -> str:
+    """
+    Create a JWT token.
+    """
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(
+            minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES
+        )
+    to_encode = {"exp": expire, "sub": str(subject)}
+    encoded_jwt = jwt.encode(to_encode, settings.SECRET_KEY, algorithm=settings.ALGORITHM)
+    return encoded_jwt
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    """
+    Verify a password against a hash.
+    """
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password: str) -> str:
+    """
+    Hash a password.
+    """
+    return pwd_context.hash(password)
--- a/app/db/init.py
+++ b/app/db/init.py
@ -0,0 +1,7 @@
+# Import all models to ensure they are registered with SQLAlchemy
+from app.db.base import Base  # noqa
+from app.models.user import User  # noqa
+from app.models.item import Item  # noqa
+from app.models.category import Category  # noqa
+from app.models.supplier import Supplier  # noqa
+from app.models.transaction import Transaction  # noqa
--- a/app/db/base.py
+++ b/app/db/base.py
@ -0,0 +1,3 @@
+from sqlalchemy.ext.declarative import declarative_base
+
+Base = declarative_base()
--- a/app/db/base_class.py
+++ b/app/db/base_class.py
@ -0,0 +1,9 @@
+from sqlalchemy import Column, Integer, DateTime
+from sqlalchemy.sql import func
+
+
+class BaseModel:
+    """Base class for all models with common fields."""
+    id = Column(Integer, primary_key=True, index=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
+    updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), nullable=False)
--- a/app/db/session.py
+++ b/app/db/session.py
@ -0,0 +1,25 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+from pathlib import Path
+
+# Create the storage/db directory if it doesn't exist
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+def get_db():
+    """Dependency for getting DB session."""
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
--- a/app/models/init.py
+++ b/app/models/init.py
--- a/app/models/category.py
+++ b/app/models/category.py
@ -0,0 +1,16 @@
+from sqlalchemy import Column, String, Text
+from sqlalchemy.orm import relationship
+
+from app.db.base import Base
+from app.db.base_class import BaseModel
+
+
+class Category(Base, BaseModel):
+    """Category model for organizing inventory items."""
+    __tablename__ = "categories"
+
+    name = Column(String, index=True, nullable=False)
+    description = Column(Text, nullable=True)
+    
+    # Relationships
+    items = relationship("Item", back_populates="category")
--- a/app/models/item.py
+++ b/app/models/item.py
@ -0,0 +1,30 @@
+from sqlalchemy import Column, String, Text, Integer, Float, ForeignKey
+from sqlalchemy.orm import relationship
+
+from app.db.base import Base
+from app.db.base_class import BaseModel
+
+
+class Item(Base, BaseModel):
+    """Inventory item model."""
+    __tablename__ = "items"
+
+    name = Column(String, index=True, nullable=False)
+    description = Column(Text, nullable=True)
+    sku = Column(String, index=True, unique=True, nullable=True)
+    barcode = Column(String, index=True, unique=True, nullable=True)
+    quantity = Column(Integer, default=0, nullable=False)
+    unit_price = Column(Float, nullable=True)
+    reorder_level = Column(Integer, default=0, nullable=True)
+    location = Column(String, nullable=True)
+    
+    # Foreign keys
+    category_id = Column(Integer, ForeignKey("categories.id"), nullable=True)
+    supplier_id = Column(Integer, ForeignKey("suppliers.id"), nullable=True)
+    owner_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    
+    # Relationships
+    category = relationship("Category", back_populates="items")
+    supplier = relationship("Supplier", back_populates="items")
+    owner = relationship("User", back_populates="items")
+    transactions = relationship("Transaction", back_populates="item")
--- a/app/models/supplier.py
+++ b/app/models/supplier.py
@ -0,0 +1,20 @@
+from sqlalchemy import Column, String, Text
+from sqlalchemy.orm import relationship
+
+from app.db.base import Base
+from app.db.base_class import BaseModel
+
+
+class Supplier(Base, BaseModel):
+    """Supplier model for inventory item sources."""
+    __tablename__ = "suppliers"
+
+    name = Column(String, index=True, nullable=False)
+    contact_name = Column(String, nullable=True)
+    email = Column(String, nullable=True)
+    phone = Column(String, nullable=True)
+    address = Column(Text, nullable=True)
+    notes = Column(Text, nullable=True)
+    
+    # Relationships
+    items = relationship("Item", back_populates="supplier")
--- a/app/models/transaction.py
+++ b/app/models/transaction.py
@ -0,0 +1,32 @@
+from sqlalchemy import Column, String, Text, Integer, Float, ForeignKey, Enum
+from sqlalchemy.orm import relationship
+import enum
+
+from app.db.base import Base
+from app.db.base_class import BaseModel
+
+
+class TransactionType(str, enum.Enum):
+    """Enum for transaction types."""
+    STOCK_IN = "stock_in"
+    STOCK_OUT = "stock_out"
+    ADJUSTMENT = "adjustment"
+
+
+class Transaction(Base, BaseModel):
+    """Transaction model for inventory movements."""
+    __tablename__ = "transactions"
+
+    transaction_type = Column(Enum(TransactionType), nullable=False)
+    quantity = Column(Integer, nullable=False)
+    unit_price = Column(Float, nullable=True)
+    reference = Column(String, nullable=True)  # Invoice/PO number
+    notes = Column(Text, nullable=True)
+    
+    # Foreign keys
+    item_id = Column(Integer, ForeignKey("items.id"), nullable=False)
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    
+    # Relationships
+    item = relationship("Item", back_populates="transactions")
+    user = relationship("User", back_populates="transactions")
--- a/app/models/user.py
+++ b/app/models/user.py
@ -0,0 +1,20 @@
+from sqlalchemy import Column, String, Boolean
+from sqlalchemy.orm import relationship
+
+from app.db.base import Base
+from app.db.base_class import BaseModel
+
+
+class User(Base, BaseModel):
+    """User model for authentication and authorization."""
+    __tablename__ = "users"
+
+    email = Column(String, unique=True, index=True, nullable=False)
+    hashed_password = Column(String, nullable=False)
+    full_name = Column(String, nullable=True)
+    is_active = Column(Boolean, default=True)
+    is_superuser = Column(Boolean, default=False)
+    
+    # Relationships
+    items = relationship("Item", back_populates="owner")
+    transactions = relationship("Transaction", back_populates="user")
--- a/app/schemas/init.py
+++ b/app/schemas/init.py
--- a/app/schemas/category.py
+++ b/app/schemas/category.py
@ -0,0 +1,30 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+
+
+class CategoryBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+
+
+class CategoryCreate(CategoryBase):
+    pass
+
+
+class CategoryUpdate(BaseModel):
+    name: Optional[str] = None
+    description: Optional[str] = None
+
+
+class CategoryInDBBase(CategoryBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+class Category(CategoryInDBBase):
+    pass
--- a/app/schemas/item.py
+++ b/app/schemas/item.py
@ -0,0 +1,47 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+
+
+class ItemBase(BaseModel):
+    name: str
+    description: Optional[str] = None
+    sku: Optional[str] = None
+    barcode: Optional[str] = None
+    quantity: int = 0
+    unit_price: Optional[float] = None
+    reorder_level: Optional[int] = None
+    location: Optional[str] = None
+    category_id: Optional[int] = None
+    supplier_id: Optional[int] = None
+
+
+class ItemCreate(ItemBase):
+    pass
+
+
+class ItemUpdate(BaseModel):
+    name: Optional[str] = None
+    description: Optional[str] = None
+    sku: Optional[str] = None
+    barcode: Optional[str] = None
+    quantity: Optional[int] = None
+    unit_price: Optional[float] = None
+    reorder_level: Optional[int] = None
+    location: Optional[str] = None
+    category_id: Optional[int] = None
+    supplier_id: Optional[int] = None
+
+
+class ItemInDBBase(ItemBase):
+    id: int
+    owner_id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+class Item(ItemInDBBase):
+    pass
--- a/app/schemas/supplier.py
+++ b/app/schemas/supplier.py
@ -0,0 +1,38 @@
+from pydantic import BaseModel, EmailStr
+from typing import Optional
+from datetime import datetime
+
+
+class SupplierBase(BaseModel):
+    name: str
+    contact_name: Optional[str] = None
+    email: Optional[EmailStr] = None
+    phone: Optional[str] = None
+    address: Optional[str] = None
+    notes: Optional[str] = None
+
+
+class SupplierCreate(SupplierBase):
+    pass
+
+
+class SupplierUpdate(BaseModel):
+    name: Optional[str] = None
+    contact_name: Optional[str] = None
+    email: Optional[EmailStr] = None
+    phone: Optional[str] = None
+    address: Optional[str] = None
+    notes: Optional[str] = None
+
+
+class SupplierInDBBase(SupplierBase):
+    id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+class Supplier(SupplierInDBBase):
+    pass
--- a/app/schemas/token.py
+++ b/app/schemas/token.py
@ -0,0 +1,10 @@
+from pydantic import BaseModel
+
+
+class Token(BaseModel):
+    access_token: str
+    token_type: str
+
+
+class TokenPayload(BaseModel):
+    sub: str = None
--- a/app/schemas/transaction.py
+++ b/app/schemas/transaction.py
@ -0,0 +1,46 @@
+from pydantic import BaseModel
+from typing import Optional
+from datetime import datetime
+from enum import Enum
+
+
+class TransactionType(str, Enum):
+    STOCK_IN = "stock_in"
+    STOCK_OUT = "stock_out"
+    ADJUSTMENT = "adjustment"
+
+
+class TransactionBase(BaseModel):
+    transaction_type: TransactionType
+    quantity: int
+    unit_price: Optional[float] = None
+    reference: Optional[str] = None
+    notes: Optional[str] = None
+    item_id: int
+
+
+class TransactionCreate(TransactionBase):
+    pass
+
+
+class TransactionUpdate(BaseModel):
+    transaction_type: Optional[TransactionType] = None
+    quantity: Optional[int] = None
+    unit_price: Optional[float] = None
+    reference: Optional[str] = None
+    notes: Optional[str] = None
+    item_id: Optional[int] = None
+
+
+class TransactionInDBBase(TransactionBase):
+    id: int
+    user_id: int
+    created_at: datetime
+    updated_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+class Transaction(TransactionInDBBase):
+    pass
--- a/app/schemas/user.py
+++ b/app/schemas/user.py
@ -0,0 +1,36 @@
+from pydantic import BaseModel, EmailStr
+from typing import Optional
+
+
+class UserBase(BaseModel):
+    email: EmailStr
+    full_name: Optional[str] = None
+    is_active: Optional[bool] = True
+    is_superuser: bool = False
+
+
+class UserCreate(UserBase):
+    password: str
+
+
+class UserUpdate(BaseModel):
+    email: Optional[EmailStr] = None
+    full_name: Optional[str] = None
+    password: Optional[str] = None
+    is_active: Optional[bool] = None
+    is_superuser: Optional[bool] = None
+
+
+class UserInDBBase(UserBase):
+    id: int
+
+    class Config:
+        from_attributes = True
+
+
+class User(UserInDBBase):
+    pass
+
+
+class UserInDB(UserInDBBase):
+    hashed_password: str
--- a/main.py
+++ b/main.py
@ -0,0 +1,46 @@
+import uvicorn
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.api.v1.api import api_router
+from app.core.config import settings
+
+app = FastAPI(
+    title=settings.PROJECT_NAME,
+    description="Small Business Inventory System API",
+    version="0.1.0",
+    openapi_url="/openapi.json",
+    docs_url="/docs",
+    redoc_url="/redoc",
+)
+
+# Add CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(api_router, prefix=settings.API_V1_STR)
+
+
+@app.get("/")
+async def root():
+    """Root endpoint with basic service information."""
+    return {
+        "title": settings.PROJECT_NAME,
+        "documentation": "/docs",
+        "health_check": "/health"
+    }
+
+
+@app.get("/health")
+async def health_check():
+    """Health check endpoint."""
+    return {"status": "healthy"}
+
+
+if __name__ == "__main__":
+    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)
--- a/migrations/init.py
+++ b/migrations/init.py
--- a/migrations/env.py
+++ b/migrations/env.py
@ -0,0 +1,87 @@
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+
+from alembic import context
+
+# Import Base from app.db.base to get all models registered
+import sys
+import os
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+from app.db.base import Base
+import app.models  # noqa
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+target_metadata = Base.metadata
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline():
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+        render_as_batch=True,  # For SQLite
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online():
+    """Run migrations in 'online' mode.
+
+    In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        is_sqlite = connection.dialect.name == 'sqlite'
+        context.configure(
+            connection=connection,
+            target_metadata=target_metadata,
+            render_as_batch=is_sqlite,  # For SQLite
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()
--- a/migrations/script.py.mako
+++ b/migrations/script.py.mako
@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade():
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade():
+    ${downgrades if downgrades else "pass"}
--- a/migrations/versions/initial_migration.py
+++ b/migrations/versions/initial_migration.py
@ -0,0 +1,129 @@
+"""Initial migration
+
+Revision ID: 01_initial
+Revises: 
+Create Date: 2023-10-23
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '01_initial'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # Create users table
+    op.create_table(
+        'users',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('email', sa.String(), nullable=False),
+        sa.Column('hashed_password', sa.String(), nullable=False),
+        sa.Column('full_name', sa.String(), nullable=True),
+        sa.Column('is_active', sa.Boolean(), nullable=True),
+        sa.Column('is_superuser', sa.Boolean(), nullable=True),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_users_email'), 'users', ['email'], unique=True)
+    op.create_index(op.f('ix_users_id'), 'users', ['id'], unique=False)
+    
+    # Create categories table
+    op.create_table(
+        'categories',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('name', sa.String(), nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_categories_id'), 'categories', ['id'], unique=False)
+    op.create_index(op.f('ix_categories_name'), 'categories', ['name'], unique=False)
+    
+    # Create suppliers table
+    op.create_table(
+        'suppliers',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('name', sa.String(), nullable=False),
+        sa.Column('contact_name', sa.String(), nullable=True),
+        sa.Column('email', sa.String(), nullable=True),
+        sa.Column('phone', sa.String(), nullable=True),
+        sa.Column('address', sa.Text(), nullable=True),
+        sa.Column('notes', sa.Text(), nullable=True),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_suppliers_id'), 'suppliers', ['id'], unique=False)
+    op.create_index(op.f('ix_suppliers_name'), 'suppliers', ['name'], unique=False)
+    
+    # Create items table
+    op.create_table(
+        'items',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('name', sa.String(), nullable=False),
+        sa.Column('description', sa.Text(), nullable=True),
+        sa.Column('sku', sa.String(), nullable=True),
+        sa.Column('barcode', sa.String(), nullable=True),
+        sa.Column('quantity', sa.Integer(), nullable=False),
+        sa.Column('unit_price', sa.Float(), nullable=True),
+        sa.Column('reorder_level', sa.Integer(), nullable=True),
+        sa.Column('location', sa.String(), nullable=True),
+        sa.Column('category_id', sa.Integer(), nullable=True),
+        sa.Column('supplier_id', sa.Integer(), nullable=True),
+        sa.Column('owner_id', sa.Integer(), nullable=False),
+        sa.ForeignKeyConstraint(['category_id'], ['categories.id'], ),
+        sa.ForeignKeyConstraint(['owner_id'], ['users.id'], ),
+        sa.ForeignKeyConstraint(['supplier_id'], ['suppliers.id'], ),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_items_barcode'), 'items', ['barcode'], unique=True)
+    op.create_index(op.f('ix_items_id'), 'items', ['id'], unique=False)
+    op.create_index(op.f('ix_items_name'), 'items', ['name'], unique=False)
+    op.create_index(op.f('ix_items_sku'), 'items', ['sku'], unique=True)
+    
+    # Create transactions table
+    op.create_table(
+        'transactions',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=False),
+        sa.Column('transaction_type', sa.Enum('STOCK_IN', 'STOCK_OUT', 'ADJUSTMENT', name='transactiontype'), nullable=False),
+        sa.Column('quantity', sa.Integer(), nullable=False),
+        sa.Column('unit_price', sa.Float(), nullable=True),
+        sa.Column('reference', sa.String(), nullable=True),
+        sa.Column('notes', sa.Text(), nullable=True),
+        sa.Column('item_id', sa.Integer(), nullable=False),
+        sa.Column('user_id', sa.Integer(), nullable=False),
+        sa.ForeignKeyConstraint(['item_id'], ['items.id'], ),
+        sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+        sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_transactions_id'), 'transactions', ['id'], unique=False)
+
+
+def downgrade():
+    op.drop_index(op.f('ix_transactions_id'), table_name='transactions')
+    op.drop_table('transactions')
+    op.drop_index(op.f('ix_items_sku'), table_name='items')
+    op.drop_index(op.f('ix_items_name'), table_name='items')
+    op.drop_index(op.f('ix_items_id'), table_name='items')
+    op.drop_index(op.f('ix_items_barcode'), table_name='items')
+    op.drop_table('items')
+    op.drop_index(op.f('ix_suppliers_name'), table_name='suppliers')
+    op.drop_index(op.f('ix_suppliers_id'), table_name='suppliers')
+    op.drop_table('suppliers')
+    op.drop_index(op.f('ix_categories_name'), table_name='categories')
+    op.drop_index(op.f('ix_categories_id'), table_name='categories')
+    op.drop_table('categories')
+    op.drop_index(op.f('ix_users_id'), table_name='users')
+    op.drop_index(op.f('ix_users_email'), table_name='users')
+    op.drop_table('users')
--- a/requirements.txt
+++ b/requirements.txt
@ -0,0 +1,11 @@
+fastapi>=0.104.0
+pydantic>=2.4.2
+pydantic-settings>=2.0.3
+sqlalchemy>=2.0.22
+alembic>=1.12.0
+uvicorn>=0.23.2
+python-jose[cryptography]>=3.3.0
+passlib[bcrypt]>=1.7.4
+python-multipart>=0.0.6
+email-validator>=2.0.0
+ruff>=0.1.1