codeocean/db/migrate/20201208095929_add_index_to_rfc.rb

class AddIndexToRfc < ActiveRecord::Migration[5.2]
  def change
    add_index(:request_for_comments, %i[user_id user_type created_at],
              order: { user_id: :asc, user_type: :asc, created_at: :desc }, name: :index_rfc_on_user_and_created_at)
  end
end