Merge pull request #2 from hoanguyen311/master

Update Project from other contributers
Modified   app/index.html
Modified   app/scripts/app.js
Merge branch 'master' of https://github.com/tuyetle/Q-A-Platform

Conflicts:
	app/scripts/app.js
Modified   app/scripts/app.js
Modified   app/scripts/controllers/question-list-controller.js
Merge pull request #6 from tuyetle/master

Adding category list