add updated_at fields

backend/main.py

@@ -141,7 +141,7 @@ def update_shop(shop_id: int, shop_update: schemas.ShopUpdate, db: Session = Dep
     if shop is None:
         raise HTTPException(status_code=404, detail="Shop not found")
     
-    update_data = shop_update.dict()
+    update_data = shop_update.dict(exclude_unset=True)
     for field, value in update_data.items():
         setattr(shop, field, value)
     

backend/models.py

@@ -40,6 +40,7 @@ class Shop(Base):
     city = Column(String, nullable=False)
     address = Column(String, nullable=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
     
     # Relationships
     shopping_events = relationship("ShoppingEvent", back_populates="shop")
@@ -53,6 +54,7 @@ class ShoppingEvent(Base):
     total_amount = Column(Float, nullable=True)  # Total cost of the shopping event
     notes = Column(String, nullable=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
     
     # Relationships
     shop = relationship("Shop", back_populates="shopping_events")

backend/schemas.py

@@ -45,6 +45,7 @@ class ShopUpdate(BaseModel):
 class Shop(ShopBase):
     id: int
     created_at: datetime
+    updated_at: Optional[datetime] = None
     
     class Config:
         from_attributes = True
@@ -87,6 +88,7 @@ class ShoppingEventUpdate(BaseModel):
 class ShoppingEventResponse(ShoppingEventBase):
     id: int
     created_at: datetime
+    updated_at: Optional[datetime] = None
     shop: Shop
     groceries: List[GroceryWithEventData] = []