Actually make index unique.

priv/repo/migrations/20170501133231_add_id_contraints_to_activities_and_objects_part_two.exs

@@ -0,0 +1,10 @@
+defmodule Pleroma.Repo.Migrations.AddIdContraintsToActivitiesAndObjectsPartTwo do
+  use Ecto.Migration
+
+  def change do
+    drop index(:objects, ["(data->>\"id\")"], name: :objects_unique_apid_index)
+    drop index(:activities, ["(data->>\"id\")"], name: :activities_unique_apid_index)
+    create unique_index(:objects, ["(data->>'id')"], name: :objects_unique_apid_index)
+    create unique_index(:activities, ["(data->>'id')"], name: :activities_unique_apid_index)
+  end
+end