index.js

var express = require('express');
var app = express();
var server = require('http').createServer(app);
//var http = require('http').Server(app);
var io = require('socket.io').listen(server);
//var port = process.env.PORT || 3000;
user = [];
connections = [];

server.listen(process.env.PORT||3000);
console.log('Server running');

app.get('/', function(req, res){
  res.sendFile(__dirname + '/index.html');
});

io.sockets.on('connection', function(socket){
    connections.push(socket);
    console.log('connected: %s socket connected', connections.length);

  //disconnect
    socket.on('disconnect', function(data){
        connections.splice(connections.indexOf(socket),1);
        console.log('Disconnected: %s sockets connected', connections.length);
    });

    socket.on('send message', function(data){
      console.log(data);
      io.sockets.emit('new message', {msg:data});
    });

});