Add DTOs for owner

backend/app/models/house.py

@@ -8,4 +8,4 @@ class House(SQLModel, table=True):
     country: str = Field()
     price: float = Field()
     description: str = Field()
-    owner_id: UUID = Field(foreign_key="user.id") # TODO consider using owner.id
+    owner_id: UUID = Field(foreign_key="owner.id")