Session authentication problems

app.js

app.use(express.bodyParser());
app.use(express.cookieParser());
app.use(express.session({secret: 'x'}));
app.use(express.static(__dirname + '/public'));
app.use(express.errorHandler({ dumpExceptions: true, showStack: true }));
app.use(app.router);

app.use(function(req, res, next) {
	if (req.session.user) {
		next();
	} else {
		res.redirect('/login');
	}
});

app.get('/', function(req, res) {
	res.redirect('/welcome');
});

app.get('/login', function(req, res) {
	res.render('login');
});