akkoma/priv/repo/migrations/20180617221540_create_activities_in_reply_to_index.exs

defmodule Pleroma.Repo.Migrations.CreateActivitiesInReplyToIndex do
  use Ecto.Migration
  @disable_ddl_transaction true

  def change do
    create(
      index(:activities, ["(data->'object'->>'inReplyTo')"],
        concurrently: true,
        name: :activities_in_reply_to
      )
    )
  end
end