# app/metal/poller.rb
  class Poller < Rails::Rack::Metal
    def call(env)
      if env["PATH_INFO"] =~ /^\/poller/
        [200, {"Content-Type" => "application/json"}, Message.recent.to_json]
      else
        super
      end
    end
  end

* There is a generator to help you get started
    `script/generate metal poller`

* Also, metal bits can be ran standalone with rackup
    `rackup app/metal/poller.rb`