When I press the login button the application does nothing!

var express = require('express');
var router = express.Router();
var User = require('../models/user');

// GET /profile
router.get('/profile', function(req, res, next) {
  if (!req.session.userId) {
    var err = new Error('You are not authorized to view this page.');
    err.status = 403;
    return next(err);
  }
  User.findById(req.session.userId).exec(function(error, user) {
    if (error) {
      return next(error);
    } else {
      return res.render('profile', {
        title: 'Profile',
        name: user.name,
        favorite: user.favoriteBook
      });
    }
  });
});

// GET /login
router.get('/login', function(req, res, next) {
  return res.render('login', { title: 'Log In' });
});

// POST /login
router.post('/login', function(req, res, next) {
  if (req.body.email && req.body.password) {
    User.authenticate(req.body.email, req.body.password, function(error, user) {
      if (error || !user) {
        var err = new Error('Wrong email or password.');
        err.status = 401;
        return next(err);
      } else {
        req.session.userId = user._id;
        return res.redirect('/profile');
      }
    });
  } else {
    var err = new Error('Email and password are required.');
    err.status = 401;
    return next(err);
  }
});

// GET /register
router.get('/register', function(req, res, next) {
  return res.render('register', { title: 'Sign Up' });
});

// POST /register
router.post('/register', function(req, res, next) {
  if (
    req.body.email &&
    req.body.name &&
    req.body.favoriteBook &&
    req.body.password &&
    req.body.confirmPassword
  ) {
    // confirm that user typed same password twice
    if (req.body.password !== req.body.confirmPassword) {
      var err = new Error('Passwords do not match.');
      err.status = 400;
      return next(err);
    }

    // create object with form input
    var userData = {
      email: req.body.email,
      name: req.body.name,
      favoriteBook: req.body.favoriteBook,
      password: req.body.password
    };

    // use schema's `create` method to insert document into Mongo
    User.create(userData, function(error, user) {
      if (error) {
        return next(error);
      } else {
        req.session.userId = user._id;
        return res.redirect('/profile');
      }
    });
  } else {
    var err = new Error('All fields required.');
    err.status = 400;
    return next(err);
  }
});

// GET /
router.get('/', function(req, res, next) {
  return res.render('index', { title: 'Home' });
});

// GET /about
router.get('/about', function(req, res, next) {
  return res.render('about', { title: 'About' });
});

// GET /contact
router.get('/contact', function(req, res, next) {
  return res.render('contact', { title: 'Contact' });
});

module.exports = router;

var express = require('express');
var bodyParser = require('body-parser');
var mongoose = require('mongoose');
var session = require('express-session');
var app = express();

// use sessions for tracking logins
app.use(
  session({
    secret: 'treehouse loves you',
    resave: true,
    saveUninitialized: false
  })
);

// make user ID available in templates
app.use(function(req, res, next) {
  res.locals.currentUser = req.session.userId;
  next();
});

// mongodb connection
mongoose.connect('mongodb://localhost:27017/bookworm');
var db = mongoose.connection;
// mongo error
db.on('error', console.error.bind(console, 'connection error:'));

// parse incoming requests
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));

// serve static files from /public
app.use(express.static(__dirname + '/public'));

// view engine setup
app.set('view engine', 'pug');
app.set('views', __dirname + '/views');

// include routes
var routes = require('./routes/index');
app.use('/', routes);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('File Not Found');
  err.status = 404;
  next(err);
});

// error handler
// define as the last app.use callback
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});

// listen on port 3000
app.listen(3000, function() {
  console.log('Express app listening on port 3000');
});

var mongoose = require('mongoose');
var bcrypt = require('bcrypt');
var UserSchema = new mongoose.Schema({
  email: {
    type: String,
    unique: true,
    required: true,
    trim: true
  },
  name: {
    type: String,
    unique: true,
    required: true,
    trim: true
  },
  favoriteBook: {
    type: String,
    unique: true,
    required: true,
    trim: true
  },
  password: {
    type: String,
    required: true
  }
});
//authenticate input against database documents
UserSchema.statics.authenticate = function(email, password, callback) {
  User.findOne({ email: email }).exec(function(error, user) {
    if (error) {
      return callback(error);
    } else if (!user) {
      var err = new Error('User not found.');
      err.status = 401;
      return callback(err);
    }
    bcrypt.compare(password, user.password, function(error, result) {});
  });
};
// hash password before saving to the database.
UserSchema.pre('save', function(next) {
  var user = this;
  bcrypt.hash(user.password, 10, function(err, hash) {
    if (err) {
      return next(err);
    }
    user.password = hash;
    next();
  });
});
var User = mongoose.model('User', UserSchema);
module.exports = User;