Socket.io listens to correct port number

[Minqi Chen]

In main.js, do this

window.socket = io.connect(":4321/");

However the port number needs to be a variable that we serve from app.js, instead of hard-coded like the example above.

[Minqi Chen]

see 0a3aa2e

[Yos Riady]

http://stackoverflow.com/questions/16098397/pass-variables-to-javascript-in-expressjs