Add some basic changesets.

lib/pleroma/object.ex

@@ -1,7 +1,7 @@
 defmodule Pleroma.Object do
   use Ecto.Schema
   alias Pleroma.{Repo, Object}
-  import Ecto.Query
+  import Ecto.{Query, Changeset}
 
   schema "objects" do
     field :data, :map
@@ -9,6 +9,13 @@ defmodule Pleroma.Object do
     timestamps()
   end
 
+  def change(struct, params \\ %{}) do
+    changeset = struct
+    |> cast(params, [:data])
+    |> validate_required([:data])
+    |> unique_constraint(:ap_id, name: :objects_unique_apid_index)
+  end
+
   def get_by_ap_id(ap_id) do
     Repo.one(from object in Object,
       where: fragment("? @> ?", object.data, ^%{id: ap_id}))