[Nodejs] Không chạy khi dùng Passport - Local để login User

Mấy bác giúp em với.
EM làm theo hướng dẫn dùng Passportjs nhưng bị lỗi không thực thi khi gán lệnh:

passport.use(new LocalStrategy(User.authenticate()));

Nếu không có lệnh trên thì em REGISTER User được, nhưng có thì nó đăng kí được nhưng không Redirect sang URL.

App.js

var express					= require('express'),
	
	mongoose				= require('mongoose'),
	passport				= require('passport'),
	bodyParser 				= require('body-parser'),
	LocalStrategy			= require('passport-local'),
	passportLocalMongoose	= require('passport-local-mongoose'),
	
	User       				= require('./models/user');


User.createStrategy();

mongoose.Promise = global.Promise;

mongoose.connect('mongodb://localhost/anhlaai1');

var app 	= express();

app.set('view engine', 'ejs');

app.use(bodyParser.urlencoded({extended: true}));

app.use(require('express-session')({
	secret: "Rusty is the best and cutest dog in my love.",
	resave: false,
	saveUninitialized: false
}));


app.use(passport.initialize());
app.use(passport.session());


passport.use(new LocalStrategy(User.authenticate()));
passport.serializeUser(User.serializeUser);
passport.deserializeUser(User.deserializeUser);


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


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

app.get('/secret', function(req, res){
	res.send('This is SECRET PAGE');
})


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


app.post('/register', function(req, res){
	req.body.username
	req.body.password


	User.register(new User({username: req.body.username}), req.body.password, function(err, user){
			if(err){
				console.log(err);
				res.redirect('/register');
			}

			passport.authenticate("local")(req, res, function(){
				res.redirect('/secret');
			});
	});
});

app.post('/login', passport.authenticate("local", {
	successRedirect: "/secret",
	failureRedirect: "/login"
}), function(req, res){

});



app.listen(3000, function(){
	console.log('Server Started!!!')
})

User.js:

var mongoose = require('mongoose');
var passportLocalMongoose = require('passport-local-mongoose');

var userSchema = new mongoose.Schema({
		username: String,
		password: String
});

userSchema.plugin(passportLocalMongoose);

module.exports = mongoose.model("User", userSchema)

Khi nó quay vòng vòng 1 hồi lâu thì hiện Error (Trong khi User tạo MỚI)

{ [UserExistsError: A user with the given username is already registered]
name: ‘UserExistsError’,
message: ‘A user with the given username is already registered’ }