Drop superflous index.

priv/repo/migrations/20171024090137_drop_object_index.exs

@@ -0,0 +1,7 @@
+defmodule Pleroma.Repo.Migrations.DropObjectIndex do
+  use Ecto.Migration
+
+  def change do
+    drop_if_exists index(:objects, [:data], using: :gin)
+  end
+end