Refactor code structure; improve organization and readability across multiple files

models/items.py

@@ -17,4 +17,11 @@ class Item(db.Model):
     inventory: Mapped[List['Inventory']] = relationship('Inventory', back_populates='item')
 
     def __repr__(self):
-        return f"<Item(id={self.id}, description={repr(self.description)}, category={repr(self.category)})>"
+        return f"<Item(id={self.id}, description={repr(self.description)}, category={repr(self.category)})>"
+    
+    def serialize(self):
+        return {
+            'id': self.id,
+            'name': self.description,
+            'category': self.category
+        }