socialforge/db/migrate/20180702025109_add_index_to_message_all.rb

class AddIndexToMessageAll < ActiveRecord::Migration
  def change
    remove_index :message_alls, name: 'index_message_alls_on_user_id_and_message_id_and_created_at'
    remove_index :message_alls, :message_type
    add_index :message_alls, [:message_id]
  end
end