Add an id index to notifications

priv/repo/migrations/20190325185009_create_notification_id_index.exs

@@ -0,0 +1,7 @@
+defmodule Pleroma.Repo.Migrations.CreateNotificationIdIndex do
+  use Ecto.Migration
+
+  def change do
+  create index(:notifications, ["id desc nulls last"])
+  end
+end