Need Help. Trying to figure out how to build a chat application like node.js example with Rainbows! and Coolio

Rainbows!+Coolio.rb

# config.ru
app = proc do |env|
  [ 200, {'Content-Type' => 'text/html'}, "hello world" ]
end

run app

# coolio_config.rb
require 'cool.io'

Rainbows! do
  use :Coolio

  HOST = 'localhost'
  PORT = 4321

  class EchoServerConnection < Cool.io::TCPSocket
    def on_connect
      puts "#{remote_addr}:#{remote_port} connected"
    end

    def on_close
      puts "#{remote_addr}:#{remote_port} disconnected"
    end

    def on_read(data)
      write data
    end
  end
  server = Cool.io::TCPServer.new(HOST, PORT, EchoServerConnection)
  server.attach(Cool.io::Loop.default)

  puts "Echo server listening on #{HOST}:#{PORT}"
  Cool.io::Loop.default.run

end