add shipment forms and start contract from form

backend/src/models.py

@@ -100,13 +100,13 @@ class FormPublic(FormBase):
     id: int
     productor: ProductorPublic | None
     referer: User | None
-    shipments: list["Shipment"] = []
+    shipments: list["ShipmentPublic"] = []
 
 class Form(FormBase, table=True):
     id: int | None = Field(default=None, primary_key=True)
     productor: Optional['Productor'] = Relationship()
     referer: Optional['User'] = Relationship()
-    shipments: list["Shipment"] = Relationship(cascade_delete=True)
+    shipments: list["Shipment"] = Relationship(back_populates="form", cascade_delete=True)
 
 class FormUpdate(SQLModel):
     name: str | None
@@ -157,15 +157,18 @@ class ShipmentBase(SQLModel):
 class ShipmentPublic(ShipmentBase):
     id: int
     products: list[Product] = []
+    form: Form | None
 
 class Shipment(ShipmentBase, table=True):
     id: int | None = Field(default=None, primary_key=True)
     products: list[Product] = Relationship(back_populates="shipments", link_model=ShipmentProductLink)
+    form: Optional[Form] = Relationship(back_populates="shipments")
 
 class ShipmentUpdate(SQLModel):
     name: str | None
     date: str | None
-    product_ids: list[int] = []
+    product_ids: list[int] | None = []
 
 class ShipmentCreate(ShipmentBase):
-    product_ids: list[int] | None
+    product_ids: list[int] = []
+    form_id: int