mailer.rb

# Requires /usr/sbin/sendmail (e.g. postfix)
module Mailer
  def self.deliver(to, subject, body)
    IO.popen("/usr/sbin/sendmail #{to}", 'w+') do |sendmail|
      sendmail.puts "Subject: #{subject}"
      sendmail.puts "From: Your Name <[email protected]>"
      sendmail.puts "To: #{to}"
      sendmail.puts body
    end
  end
end