use helmet module to more secure application

Helmet module is the middleware to add security headers for Application.
I think these headers is so important for security that we should also use in MEAN.js.

We need to install the latest one from github currently because it looks old on the npm site.
The old one is not working on my local MEAN.js stack.

config/express.js

@@ -10,6 +10,7 @@ var express = require('express'),
 	config = require('./config'),
 	consolidate = require('consolidate'),
 	path = require('path'),
+	helmet = require('helmet'),
 	utilities = require('./utilities');
 
 module.exports = function(db) {
@@ -98,6 +99,8 @@ module.exports = function(db) {
 	// connect flash for flash messages
 	app.use(flash());
 
+	app.use(helmet.defaults());
+
 	// routes should be at the last
 	app.use(app.router);
 

package.json

@@ -33,7 +33,8 @@
 		"lodash": "~2.4.1",
 		"forever": "~0.10.11",
 		"bower": "~1.3.1",
-		"grunt-cli": "~0.1.13"
+		"grunt-cli": "~0.1.13",
+		"helmet": "git://github.com/evilpacket/helmet.git"
 	},
 	"devDependencies": {
 		"supertest": "~0.9.0",