Add Book model

models/book.py

@@ -1,20 +1,19 @@
 from sqlalchemy import Column, String, Integer, Boolean, DateTime, ForeignKey
+from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
 from core.database import Base
 import uuid
+from datetime import datetime
 
 class Book(Base):
     __tablename__ = "books"
-    
     id = Column(String, primary_key=True, default=lambda: str(uuid.uuid4()))
     title = Column(String, nullable=False, index=True)
     author = Column(String, nullable=False)
-    isbn = Column(String, unique=True, nullable=False)
-    publication_year = Column(Integer)
-    publisher = Column(String)
     description = Column(String)
-    copies_available = Column(Integer, default=1)
+    isbn = Column(String, unique=True)
+    price = Column(Integer, nullable=False)
+    quantity = Column(Integer, default=0)
     is_available = Column(Boolean, default=True)
-    
     created_at = Column(DateTime, default=func.now())
     updated_at = Column(DateTime, default=func.now(), onupdate=func.now())