Attach actor to pictures entity

lib/mobilizon/media/picture.ex

@@ -5,9 +5,11 @@ defmodule Mobilizon.Media.Picture do
   use Ecto.Schema
   import Ecto.Changeset
   alias Mobilizon.Media.File
+  alias Mobilizon.Actors.Actor
 
   schema "pictures" do
     embeds_one(:file, File, on_replace: :update)
+    belongs_to(:actor, Actor)
 
     timestamps()
   end
@@ -15,7 +17,7 @@ defmodule Mobilizon.Media.Picture do
   @doc false
   def changeset(picture, attrs) do
     picture
-    |> cast(attrs, [])
+    |> cast(attrs, [:actor_id])
     |> cast_embed(:file)
   end
 end