class AASM::Base

def setup_timestamps(aasm_name)
  return unless @state_machine.config.timestamps
  after_all_transitions do
    if self.class.aasm(:"#{aasm_name}").state_machine.config.timestamps
      ts_setter = "#{aasm(aasm_name).to_state}_at="
      respond_to?(ts_setter) && send(ts_setter, ::Time.now)
    end
  end
end