diff --git a/README.md b/README.md
index 50381e3..7d4086a 100644
--- a/README.md
+++ b/README.md
@@ -1,10 +1,13 @@
 # SimpleTodoApp API
 
-A FastAPI-based backend for a simple Todo application with SQLite database.
+A FastAPI-based backend for a simple Todo application with SQLite database and user authentication.
 
 ## Features
 
-- Create, read, update, and delete Todo items
+- User registration and authentication with JWT tokens
+- Create, read, update, and delete Todo items (protected by authentication)
+- User-specific Todo items
+- Role-based access control (regular users and superusers)
 - Health check endpoint
 - SQLite database with SQLAlchemy ORM
 - Database migrations with Alembic
@@ -16,8 +19,19 @@ A FastAPI-based backend for a simple Todo application with SQLite database.
 simpletodoapp/
 ├── api/                  # API-related code
 │   ├── crud/             # CRUD operations
+│   │   ├── todo.py       # Todo CRUD operations
+│   │   └── user.py       # User CRUD operations
 │   ├── routers/          # API endpoints
-│   └── schemas/          # Pydantic models for request/response validation
+│   │   ├── auth_router.py     # Authentication endpoints
+│   │   ├── health_router.py   # Health check endpoint
+│   │   ├── todo_router.py     # Todo endpoints
+│   │   └── user_router.py     # User endpoints
+│   ├── schemas/          # Pydantic models for request/response validation
+│   │   ├── health.py     # Health check schemas
+│   │   ├── todo.py       # Todo schemas
+│   │   └── user.py       # User and authentication schemas
+│   └── utils/            # Utility functions
+│       └── auth.py       # Authentication utilities
 ├── db/                   # Database-related code
 │   ├── database.py       # Database connection and session
 │   └── models.py         # SQLAlchemy models
@@ -34,11 +48,28 @@ simpletodoapp/
    ```
    pip install -r requirements.txt
    ```
-3. Run the application:
+3. Apply database migrations:
+   ```
+   alembic upgrade head
+   ```
+4. Run the application:
    ```
    uvicorn main:app --reload
    ```
 
+## Authentication
+
+The API uses JWT (JSON Web Tokens) for authentication. To use protected endpoints:
+
+1. Register a new user using `POST /api/users`
+2. Get an access token using `POST /api/auth/token` with your username and password
+3. Include the token in the `Authorization` header of your requests:
+   ```
+   Authorization: Bearer <your_token>
+   ```
+
+Access tokens expire after 30 minutes by default.
+
 ## API Documentation
 
 Once the server is running, you can access:
@@ -47,9 +78,29 @@ Once the server is running, you can access:
 
 ## API Endpoints
 
-- `GET /api/health` - Health check endpoint
-- `GET /api/todos` - List all todos
-- `GET /api/todos/{id}` - Get a single todo by ID
-- `POST /api/todos` - Create a new todo
-- `PATCH /api/todos/{id}` - Update a todo (partial update)
-- `DELETE /api/todos/{id}` - Delete a todo
\ No newline at end of file
+### Authentication
+
+- `POST /api/auth/token` - Get access token (login)
+- `POST /api/users` - Register a new user
+
+### Users
+
+- `GET /api/users/me` - Get current user information
+- `PUT /api/users/me` - Update current user information
+- `GET /api/users/{id}` - Get user information by ID (current user or superuser only)
+- `GET /api/users` - List all users (superuser only)
+- `DELETE /api/users/{id}` - Delete a user (superuser only)
+
+### Todos
+
+All todo endpoints require authentication.
+
+- `GET /api/todos` - List all todos for current user
+- `GET /api/todos/{id}` - Get a single todo by ID (owned by current user)
+- `POST /api/todos` - Create a new todo (owned by current user)
+- `PATCH /api/todos/{id}` - Update a todo (owned by current user)
+- `DELETE /api/todos/{id}` - Delete a todo (owned by current user)
+
+### Health
+
+- `GET /api/health` - Health check endpoint
\ No newline at end of file
diff --git a/api/crud/todo.py b/api/crud/todo.py
index 6989485..c64dd7d 100644
--- a/api/crud/todo.py
+++ b/api/crud/todo.py
@@ -6,36 +6,36 @@ from api.schemas.todo import TodoCreate, TodoUpdate
 from db.models import Todo
 
 
-def get_todos(db: Session, skip: int = 0, limit: int = 100) -> list[Todo]:
+def get_todos(db: Session, user_id: int, skip: int = 0, limit: int = 100) -> list[Todo]:
     """
-    Get all todos with pagination
+    Get all todos for a user with pagination
     """
-    return db.query(Todo).offset(skip).limit(limit).all()
+    return db.query(Todo).filter(Todo.owner_id == user_id).offset(skip).limit(limit).all()
 
 
-def get_todo(db: Session, todo_id: int) -> Optional[Todo]:
+def get_todo(db: Session, todo_id: int, user_id: int) -> Optional[Todo]:
     """
-    Get a specific todo by ID
+    Get a specific todo by ID for a specific user
     """
-    return db.query(Todo).filter(Todo.id == todo_id).first()
+    return db.query(Todo).filter(Todo.id == todo_id, Todo.owner_id == user_id).first()
 
 
-def create_todo(db: Session, todo: TodoCreate) -> Todo:
+def create_todo(db: Session, todo: TodoCreate, user_id: int) -> Todo:
     """
-    Create a new todo
+    Create a new todo for a user
     """
-    db_todo = Todo(**todo.dict())
+    db_todo = Todo(**todo.dict(), owner_id=user_id)
     db.add(db_todo)
     db.commit()
     db.refresh(db_todo)
     return db_todo
 
 
-def update_todo(db: Session, todo_id: int, todo: TodoUpdate) -> Optional[Todo]:
+def update_todo(db: Session, todo_id: int, todo: TodoUpdate, user_id: int) -> Optional[Todo]:
     """
-    Update an existing todo
+    Update an existing todo for a user
     """
-    db_todo = get_todo(db, todo_id)
+    db_todo = get_todo(db, todo_id, user_id)
     if db_todo is None:
         return None
 
@@ -49,12 +49,12 @@ def update_todo(db: Session, todo_id: int, todo: TodoUpdate) -> Optional[Todo]:
     return db_todo
 
 
-def delete_todo(db: Session, todo_id: int) -> bool:
+def delete_todo(db: Session, todo_id: int, user_id: int) -> bool:
     """
-    Delete a todo by ID
+    Delete a todo by ID for a user
     Returns True if the todo was deleted, False if it didn't exist
     """
-    db_todo = get_todo(db, todo_id)
+    db_todo = get_todo(db, todo_id, user_id)
     if db_todo is None:
         return False
 
diff --git a/api/crud/user.py b/api/crud/user.py
new file mode 100644
index 0000000..f17788c
--- /dev/null
+++ b/api/crud/user.py
@@ -0,0 +1,84 @@
+from typing import Optional
+
+from sqlalchemy.orm import Session
+
+from api.schemas.user import UserCreate, UserUpdate
+from api.utils.auth import get_password_hash
+from db.models import User
+
+
+def get_user(db: Session, user_id: int) -> Optional[User]:
+    """
+    Get a user by ID
+    """
+    return db.query(User).filter(User.id == user_id).first()
+
+
+def get_user_by_email(db: Session, email: str) -> Optional[User]:
+    """
+    Get a user by email
+    """
+    return db.query(User).filter(User.email == email).first()
+
+
+def get_user_by_username(db: Session, username: str) -> Optional[User]:
+    """
+    Get a user by username
+    """
+    return db.query(User).filter(User.username == username).first()
+
+
+def get_users(db: Session, skip: int = 0, limit: int = 100) -> list[User]:
+    """
+    Get all users with pagination
+    """
+    return db.query(User).offset(skip).limit(limit).all()
+
+
+def create_user(db: Session, user: UserCreate) -> User:
+    """
+    Create a new user
+    """
+    hashed_password = get_password_hash(user.password)
+    db_user = User(
+        email=user.email,
+        username=user.username,
+        hashed_password=hashed_password,
+    )
+    db.add(db_user)
+    db.commit()
+    db.refresh(db_user)
+    return db_user
+
+
+def update_user(db: Session, user_id: int, user: UserUpdate) -> Optional[User]:
+    """
+    Update an existing user
+    """
+    db_user = get_user(db, user_id)
+    if db_user is None:
+        return None
+
+    update_data = user.dict(exclude_unset=True)
+    if "password" in update_data:
+        update_data["hashed_password"] = get_password_hash(update_data.pop("password"))
+
+    for key, value in update_data.items():
+        setattr(db_user, key, value)
+
+    db.commit()
+    db.refresh(db_user)
+    return db_user
+
+
+def delete_user(db: Session, user_id: int) -> bool:
+    """
+    Delete a user
+    """
+    db_user = get_user(db, user_id)
+    if db_user is None:
+        return False
+
+    db.delete(db_user)
+    db.commit()
+    return True
diff --git a/api/routers/auth_router.py b/api/routers/auth_router.py
new file mode 100644
index 0000000..febd091
--- /dev/null
+++ b/api/routers/auth_router.py
@@ -0,0 +1,39 @@
+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 api.schemas.user import Token
+from api.utils.auth import (
+    ACCESS_TOKEN_EXPIRE_MINUTES,
+    authenticate_user,
+    create_access_token,
+)
+from db.database import get_db
+
+router = APIRouter()
+
+
+@router.post("/token", response_model=Token)
+def login_for_access_token(
+    form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db),
+) -> Any:
+    """
+    Generate JWT token for authenticated user
+    """
+    user = authenticate_user(db, form_data.username, form_data.password)
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect username or password",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
+    access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
+    access_token = create_access_token(
+        data={"sub": user.username}, expires_delta=access_token_expires,
+    )
+
+    return {"access_token": access_token, "token_type": "bearer"}
diff --git a/api/routers/todo_router.py b/api/routers/todo_router.py
index 6c8eee9..c7efa39 100644
--- a/api/routers/todo_router.py
+++ b/api/routers/todo_router.py
@@ -3,56 +3,80 @@ from sqlalchemy.orm import Session
 
 from api.crud.todo import create_todo, delete_todo, get_todo, get_todos, update_todo
 from api.schemas.todo import TodoCreate, TodoResponse, TodoUpdate
+from api.utils.auth import get_current_active_user
 from db.database import get_db
+from db.models import User
 
 router = APIRouter()
 
 
 @router.get("/", response_model=list[TodoResponse])
-def read_todos(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
+def read_todos(
+    skip: int = 0,
+    limit: int = 100,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user),
+):
     """
-    Get all todos with pagination
+    Get all todos for the current user with pagination
     """
-    todos = get_todos(db, skip=skip, limit=limit)
+    todos = get_todos(db, user_id=current_user.id, skip=skip, limit=limit)
     return todos
 
 
 @router.get("/{todo_id}", response_model=TodoResponse)
-def read_todo(todo_id: int, db: Session = Depends(get_db)):
+def read_todo(
+    todo_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user),
+):
     """
-    Get a specific todo by ID
+    Get a specific todo by ID for the current user
     """
-    db_todo = get_todo(db, todo_id=todo_id)
+    db_todo = get_todo(db, todo_id=todo_id, user_id=current_user.id)
     if db_todo is None:
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found")
     return db_todo
 
 
 @router.post("/", response_model=TodoResponse, status_code=status.HTTP_201_CREATED)
-def create_new_todo(todo: TodoCreate, db: Session = Depends(get_db)):
+def create_new_todo(
+    todo: TodoCreate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user),
+):
     """
-    Create a new todo
+    Create a new todo for the current user
     """
-    return create_todo(db=db, todo=todo)
+    return create_todo(db=db, todo=todo, user_id=current_user.id)
 
 
 @router.patch("/{todo_id}", response_model=TodoResponse)
-def update_existing_todo(todo_id: int, todo: TodoUpdate, db: Session = Depends(get_db)):
+def update_existing_todo(
+    todo_id: int,
+    todo: TodoUpdate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user),
+):
     """
-    Update an existing todo (partial update)
+    Update an existing todo (partial update) for the current user
     """
-    db_todo = update_todo(db=db, todo_id=todo_id, todo=todo)
+    db_todo = update_todo(db=db, todo_id=todo_id, todo=todo, user_id=current_user.id)
     if db_todo is None:
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found")
     return db_todo
 
 
 @router.delete("/{todo_id}", status_code=status.HTTP_204_NO_CONTENT)
-def delete_existing_todo(todo_id: int, db: Session = Depends(get_db)):
+def delete_existing_todo(
+    todo_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user),
+):
     """
-    Delete a todo
+    Delete a todo for the current user
     """
-    success = delete_todo(db=db, todo_id=todo_id)
+    success = delete_todo(db=db, todo_id=todo_id, user_id=current_user.id)
     if not success:
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Todo not found")
     return None
diff --git a/api/routers/user_router.py b/api/routers/user_router.py
new file mode 100644
index 0000000..e350c72
--- /dev/null
+++ b/api/routers/user_router.py
@@ -0,0 +1,110 @@
+from fastapi import APIRouter, Depends, HTTPException, status
+from sqlalchemy.orm import Session
+
+from api.crud.user import (
+    create_user,
+    delete_user,
+    get_user,
+    get_user_by_email,
+    get_user_by_username,
+    get_users,
+    update_user,
+)
+from api.schemas.user import UserCreate, UserResponse, UserUpdate
+from api.utils.auth import get_current_active_user, get_current_superuser
+from db.database import get_db
+from db.models import User
+
+router = APIRouter()
+
+
+@router.get("/", response_model=list[UserResponse])
+def read_users(
+    skip: int = 0,
+    limit: int = 100,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_superuser),
+) -> list[User]:
+    """
+    Get all users with pagination (superuser only)
+    """
+    users = get_users(db, skip=skip, limit=limit)
+    return users
+
+
+@router.get("/me", response_model=UserResponse)
+def read_user_me(current_user: User = Depends(get_current_active_user)) -> User:
+    """
+    Get current user
+    """
+    return current_user
+
+
+@router.put("/me", response_model=UserResponse)
+def update_user_me(
+    user: UserUpdate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user),
+) -> User:
+    """
+    Update current user
+    """
+    # Prevent user from changing themselves to superuser
+    if user.is_superuser is not None:
+        user.is_superuser = current_user.is_superuser
+
+    return update_user(db, current_user.id, user)
+
+
+@router.get("/{user_id}", response_model=UserResponse)
+def read_user(
+    user_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_active_user),
+) -> User:
+    """
+    Get a specific user by ID (superuser or same user)
+    """
+    db_user = get_user(db, user_id=user_id)
+    if db_user is None:
+        raise HTTPException(status_code=404, detail="User not found")
+    if current_user.id != user_id and not current_user.is_superuser:
+        raise HTTPException(status_code=403, detail="Not enough permissions")
+    return db_user
+
+
+@router.post("/", response_model=UserResponse, status_code=status.HTTP_201_CREATED)
+def register_user(user: UserCreate, db: Session = Depends(get_db)) -> User:
+    """
+    Register a new user
+    """
+    db_user_by_email = get_user_by_email(db, email=user.email)
+    if db_user_by_email:
+        raise HTTPException(
+            status_code=400,
+            detail="Email already registered",
+        )
+
+    db_user_by_username = get_user_by_username(db, username=user.username)
+    if db_user_by_username:
+        raise HTTPException(
+            status_code=400,
+            detail="Username already taken",
+        )
+
+    return create_user(db=db, user=user)
+
+
+@router.delete("/{user_id}", status_code=status.HTTP_204_NO_CONTENT)
+def delete_user_by_id(
+    user_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_superuser),
+) -> None:
+    """
+    Delete a user (superuser only)
+    """
+    success = delete_user(db=db, user_id=user_id)
+    if not success:
+        raise HTTPException(status_code=404, detail="User not found")
+    return None
diff --git a/api/schemas/user.py b/api/schemas/user.py
new file mode 100644
index 0000000..e03a7da
--- /dev/null
+++ b/api/schemas/user.py
@@ -0,0 +1,51 @@
+from datetime import datetime
+from typing import Optional
+
+from pydantic import BaseModel, EmailStr, Field
+
+
+class UserBase(BaseModel):
+    """Base User schema with common attributes"""
+    email: EmailStr = Field(..., description="User email address")
+    username: str = Field(..., min_length=3, max_length=50, description="User username")
+
+
+class UserCreate(UserBase):
+    """Schema for creating a new user"""
+    password: str = Field(..., min_length=8, description="User password")
+
+
+class UserUpdate(BaseModel):
+    """Schema for updating an existing user, all fields are optional"""
+    email: Optional[EmailStr] = Field(None, description="User email address")
+    username: Optional[str] = Field(
+        None, min_length=3, max_length=50, description="User username",
+    )
+    password: Optional[str] = Field(None, min_length=8, description="User password")
+    is_active: Optional[bool] = Field(None, description="User active status")
+    is_superuser: Optional[bool] = Field(None, description="User superuser status")
+
+
+class UserResponse(UserBase):
+    """Schema for user response that includes database fields"""
+    id: int
+    is_active: bool
+    is_superuser: bool
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        """ORM mode config for the UserResponse schema"""
+        orm_mode = True
+        from_attributes = True
+
+
+class Token(BaseModel):
+    """Schema for JWT token"""
+    access_token: str
+    token_type: str
+
+
+class TokenData(BaseModel):
+    """Schema for JWT token data"""
+    username: Optional[str] = None
diff --git a/api/utils/__init__.py b/api/utils/__init__.py
new file mode 100644
index 0000000..b5027a8
--- /dev/null
+++ b/api/utils/__init__.py
@@ -0,0 +1 @@
+"""API utility functions"""
diff --git a/api/utils/auth.py b/api/utils/auth.py
new file mode 100644
index 0000000..e6f71dd
--- /dev/null
+++ b/api/utils/auth.py
@@ -0,0 +1,94 @@
+from datetime import datetime, timedelta
+from typing import Optional, Union
+
+from fastapi import Depends, HTTPException, status
+from fastapi.security import OAuth2PasswordBearer
+from jose import JWTError, jwt
+from passlib.context import CryptContext
+from sqlalchemy.orm import Session
+
+from api.schemas.user import TokenData
+from db.database import get_db
+from db.models import User
+
+# to get a string like this run: openssl rand -hex 32
+# In production, this should be stored in environment variables
+SECRET_KEY = "09d25e094faa6ca2556c818166b7a9563b93f7099f6f0f4caa6cf63b88e8d3e7"  # noqa: S105
+ALGORITHM = "HS256"
+ACCESS_TOKEN_EXPIRE_MINUTES = 30
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl="api/auth/token")
+
+
+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)
+
+
+def authenticate_user(db: Session, username: str, password: str) -> Union[User, bool]:
+    """Authenticate a user"""
+    user = db.query(User).filter(User.username == username).first()
+    if not user or not verify_password(password, user.hashed_password):
+        return False
+    if not user.is_active:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST, detail="Inactive user",
+        )
+    return user
+
+
+def create_access_token(data: dict, expires_delta: Optional[timedelta] = None) -> str:
+    """Create a JWT token"""
+    to_encode = data.copy()
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
+    to_encode.update({"exp": expire})
+    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
+    return encoded_jwt
+
+
+async def get_current_user(
+    token: str = Depends(oauth2_scheme), db: Session = Depends(get_db),
+) -> User:
+    """Get the current user from a JWT token"""
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+        username: str = payload.get("sub")
+        if username is None:
+            raise credentials_exception
+        token_data = TokenData(username=username)
+    except JWTError as err:
+        raise credentials_exception from err
+    user = db.query(User).filter(User.username == token_data.username).first()
+    if user is None or not user.is_active:
+        raise credentials_exception
+    return user
+
+
+async def get_current_active_user(current_user: User = Depends(get_current_user)) -> User:
+    """Get the current active user"""
+    if not current_user.is_active:
+        raise HTTPException(status_code=400, detail="Inactive user")
+    return current_user
+
+
+async def get_current_superuser(current_user: User = Depends(get_current_user)) -> User:
+    """Get the current superuser"""
+    if not current_user.is_superuser:
+        raise HTTPException(
+            status_code=status.HTTP_403_FORBIDDEN, detail="Not enough permissions",
+        )
+    return current_user
diff --git a/db/models.py b/db/models.py
index 3054722..e8aaeaf 100644
--- a/db/models.py
+++ b/db/models.py
@@ -1,9 +1,28 @@
-from sqlalchemy import Boolean, Column, DateTime, Integer, String
+from sqlalchemy import Boolean, Column, DateTime, ForeignKey, Integer, String
+from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
 
 from .database import Base
 
 
+class User(Base):
+    """
+    User model for authentication and authorization
+    """
+    __tablename__ = "users"
+
+    id = Column(Integer, primary_key=True, index=True)
+    email = Column(String, unique=True, index=True, nullable=False)
+    username = Column(String, unique=True, index=True, nullable=False)
+    hashed_password = Column(String, nullable=False)
+    is_active = Column(Boolean, default=True)
+    is_superuser = Column(Boolean, default=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    todos = relationship("Todo", back_populates="owner", cascade="all, delete-orphan")
+
+
 class Todo(Base):
     """
     Todo model representing a task to be done
@@ -16,3 +35,7 @@ class Todo(Base):
     completed = Column(Boolean, default=False)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
     updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    # Add relationship to User
+    owner_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    owner = relationship("User", back_populates="todos")
diff --git a/main.py b/main.py
index 343603a..1aff3b6 100644
--- a/main.py
+++ b/main.py
@@ -2,12 +2,12 @@ import uvicorn
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
-from api.routers import health_router, todo_router
+from api.routers import auth_router, health_router, todo_router, user_router
 from db.database import create_tables
 
 app = FastAPI(
     title="SimpleTodoApp API",
-    description="API for a simple todo application",
+    description="API for a simple todo application with authentication",
     version="0.1.0",
 )
 
@@ -21,6 +21,8 @@ app.add_middleware(
 )
 
 # Include routers
+app.include_router(auth_router.router, prefix="/api/auth", tags=["auth"])
+app.include_router(user_router.router, prefix="/api/users", tags=["users"])
 app.include_router(todo_router.router, prefix="/api/todos", tags=["todos"])
 app.include_router(health_router.router, prefix="/api", tags=["health"])
 
diff --git a/migrations/versions/2_add_users_table_and_update_todos.py b/migrations/versions/2_add_users_table_and_update_todos.py
new file mode 100644
index 0000000..7a64b4f
--- /dev/null
+++ b/migrations/versions/2_add_users_table_and_update_todos.py
@@ -0,0 +1,69 @@
+"""Add users table and update todos
+
+Revision ID: 2_add_users_table_and_update_todos
+Revises: 1_initial_create_todos_table
+Create Date: 2023-07-20 10:00:00.000000
+
+"""
+import sqlalchemy as sa
+from alembic import op
+
+# revision identifiers, used by Alembic.
+revision = '2_add_users_table_and_update_todos'
+down_revision = '1_initial_create_todos_table'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # Create users table
+    op.create_table(
+        'users',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('email', sa.String(), nullable=False),
+        sa.Column('username', sa.String(), nullable=False),
+        sa.Column('hashed_password', sa.String(), nullable=False),
+        sa.Column('is_active', sa.Boolean(), nullable=True, default=True),
+        sa.Column('is_superuser', sa.Boolean(), nullable=True, default=False),
+        sa.Column(
+            'created_at',
+            sa.DateTime(timezone=True),
+            server_default=sa.text('(CURRENT_TIMESTAMP)'),
+            nullable=True,
+        ),
+        sa.Column('updated_at', sa.DateTime(timezone=True), 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)
+    op.create_index(op.f('ix_users_username'), 'users', ['username'], unique=True)
+
+    # Add owner_id column to todos table
+    op.add_column('todos', sa.Column('owner_id', sa.Integer(), nullable=True))
+
+    # Create foreign key from todos to users
+    op.create_foreign_key(
+        'fk_todos_owner_id_users',
+        'todos', 'users',
+        ['owner_id'], ['id'],
+    )
+
+    # Update all existing todos to have owner_id = 1 (first user)
+    op.execute("UPDATE todos SET owner_id = 1")
+
+    # Make owner_id non-nullable after updating existing todos
+    op.alter_column('todos', 'owner_id', nullable=False)
+
+
+def downgrade():
+    # Drop foreign key constraint
+    op.drop_constraint('fk_todos_owner_id_users', 'todos', type_='foreignkey')
+
+    # Drop owner_id column from todos
+    op.drop_column('todos', 'owner_id')
+
+    # Drop users table
+    op.drop_index(op.f('ix_users_username'), table_name='users')
+    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')
diff --git a/requirements.txt b/requirements.txt
index 7dba23f..cd5c8f9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,4 +6,7 @@ alembic>=1.11.1
 ruff>=0.0.280
 python-dotenv>=1.0.0
 python-multipart>=0.0.6
-pathlib>=1.0.1
\ No newline at end of file
+pathlib>=1.0.1
+passlib>=1.7.4
+python-jose>=3.3.0
+bcrypt>=4.0.1
\ No newline at end of file