old_contents: var app = require('express')();
  var http = require('http').Server(app);
  var io = require('socket.io')(http);
  
  app.get('/', function(req, res){
  	res.send('<h1>Welcome Realtime Server</h1>');
  });
  
  http.listen(3000, function(){
  	console.log('listening on *:6027');
  });
new_contents: var app = require('express')();
  var http = require('http').Server(app);
  var io = require('socket.io')(http);
  
  app.get('/', function(req, res){
  	res.send('<h1>Welcome Realtime Server</h1>');
  });
  
  http.listen(6027, function(){
  	console.log('listening on *:6027');
  });
subject: fix listen port