fix db errror

backend/models.py

@@ -83,20 +83,13 @@ class Product(Base):
     shopping_events = relationship("ShoppingEvent", secondary=shopping_event_products, back_populates="products")
     
     # Self-referential many-to-many relationship for related products
+    # We'll use a simpler approach without back_populates to avoid circular references
     related_products = relationship(
         "Product",
         secondary=related_products,
-        primaryjoin=id == related_products.c.product_id,
-        secondaryjoin=id == related_products.c.related_product_id,
-        back_populates="related_to_products"
-    )
-    
-    related_to_products = relationship(
-        "Product",
-        secondary=related_products,
-        primaryjoin=id == related_products.c.related_product_id,
-        secondaryjoin=id == related_products.c.product_id,
-        back_populates="related_products"
+        primaryjoin="Product.id == related_products.c.product_id",
+        secondaryjoin="Product.id == related_products.c.related_product_id",
+        viewonly=True
     )
 
 class Shop(Base):

backend/schemas.py

@@ -173,6 +173,7 @@ class ShopStats(BaseModel):
 
 # Update forward references
 BrandInShop.model_rebuild()
+ProductWithRelated.model_rebuild()
 
 # Related Products schemas
 class RelatedProductBase(BaseModel):