how to process incoming mails using mailman and update them into the database

am developing ruby on rails3 application where i am sending an email to user and if user replies that email then that reply content, date should be updated to the database. For this i have ProductComment model. when admin sends comment to the user it will be stored in the database. if user replies to that then database should be updated accordingly. I am trying to use mailman. I have installed the gem. But am not getting how to get the comment id, what should i write in replyto address, where to write the mailman code and from which mail i should read.

Am sending email like this:

mail(:to => @user.email, :subject => "Edit Your Product", :reply_to=>"abc@syz.com)

I am handling it in products controller like this:

require 'mailman'
Mailman::Application.run do
to 'abc@xyz.com' do
ProductComment.create(message)
end
end

Please help me to come out from this problem

Please tell me how to use mailman gem in ruby on rails3 application

there is a recent pro-episode on receiving emails with mailman on railscasts: http://railscasts.com/episodes/313-receiving-email-with-mailman

chmod +x script/mailman_server
cat mailman_test.eml | script/mailman_server
script/mailman_server

-

# script/mailman_server
#!/usr/bin/env ruby
require "rubygems"
require "bundler/setup"
require "mailman"

Mailman.config.logger = Logger.new("log/mailman.log")

Mailman.config.pop3 = {
  server: 'pop.gmail.com', port: 995, ssl: true,
  username: ENV["GMAIL_USERNAME"],
  password: ENV["GMAIL_PASSWORD"]
}

Mailman::Application.run do
  default do
    begin
      Ticket.receive_mail(message)
    rescue Exception => e
      Mailman.logger.error "Exception occurred while receiving message:\n#{message}"
      Mailman.logger.error [e, *e.backtrace].join("\n")
    end
  end
end

-

def self.receive_mail(message)
  ticket_id = message.subject[/^Update (\d+)$/, 1]
  if ticket_id.present? && Ticket.exists?(ticket_id)
    Ticket.update(ticket_id, body: message.body.decoded)
  else
    Ticket.create subject: message.subject, body: message.body.decoded, from: message.from.first
  end
end