gistfile1.rb

# app/models/user.rb
class User

  class << self
   
    def async_spam_all(email_text)
      Queue::Normal.enqueue(self, :spam_all, email_text)
    end

    def spam_all(email_text)
      find_each { |user| UserMailer.spam(user, email_text).deliver }
    end
  end
end