Override Devise email logic for sending asynchronously with Sidekiq

devise_async.rb

module DeviseAsync
  #######################################################################
  # Override Devise email logic for sending asynchronously with Sidekiq #
  #######################################################################

  def self.included(clazz)
    clazz.class_eval do
      public

      after_commit :send_pending_notifications  

      protected

      # If the resource has been changed, wait until the after_commit flag is fired before sending the notification       
      def send_devise_notification(notification)
        if self.changed?
          pending_notifications << notification
        else
          devise_mailer.delay.send(n, self)
        end
      end

      def send_pending_notifications
        pending_notifications.each do |n|
          devise_mailer.delay.send(n, self)
        end
      end

      def pending_notifications
        @pending_notifications ||= []
      end

    end
  end

end