[WIP] front api exchanges

backend/src/models.py

@@ -45,6 +45,7 @@ class ProductorCreate(ProductorBase):
 class Unit(Enum):
     GRAMS = 1
     KILO = 2
+    PIECE = 3
 
 class ProductType(Enum):
     PLANNED = 1
@@ -96,7 +97,7 @@ class FormBase(SQLModel):
 class FormPublic(FormBase):
     id: int
     productor: ProductorPublic | None
-    referer: User
+    referer: User | None
     shipments: list["Shipment"] = []
 
 class Form(FormBase, table=True):
@@ -164,4 +165,4 @@ class ShipmentUpdate(SQLModel):
     product_ids: list[int]
 
 class ShipmentCreate(ShipmentBase):
-    product_ids: list[int]
+    product_ids: list[int] | None