dip_example_1.rb

class EmailList
  attr_reader :mailer
  delegate :send_email, :to => :mailer
  def initialize
    @mailer = MailerMonkey.new
  end
end
# in RottenPotatoes EmailListController:
def advertise_discount_for_movie
  moviegoers = Moviegoer.interested_in params[:movie_id]
  EmailList.new.send_email_to moviegoers
end