Cannot GET/ error while opening my app - node.js

Question

-> this is my server.js. while i am trying to open it by using node server, it is showing cannot get/.
-> as i am trying to open. it is showing cannot get/. I have routed all the links correctly. but still this issue is pertaining me.
-> in my server it is showing mongodb connected and running. but whilw i open it it is showing cannot get/
var express = require('express');
var bodyParser = require('body-parser');
var User = require('./app/models/user');
var app = express();
var jwt = require('jwt-simple') var _ = require('lodash') var bcrypt = require('bcrypt')
app.use(bodyParser.json()); // support json encoded bodies app.use(bodyParser.urlencoded({ extended: true })); // support encoded bodies
var secretkey = "supersecretkey"
app.post('/session', function(req, res, next) {
console.log(req.body.username);
User.findOne({
username: req.body.username
}).select('password').exec(function(err, user) {
if (err) {
return next(err)
}
if (!user) {
return res.send(401)
}
bcrypt.compare(req.body.password, user.password, function(err, valid) {
if (err) {
return next(err)
}
if (!valid) {
return res.send(401)
} //var test = {username:user.username}; //console.log(user.username); var token = jwt.encode({ username: req.body.username}, secretkey) res.json(token)
})
})
})
app.get('/user', function(req, res, next) {
var token = req.headers['x-auth'] console.log(token)
var auth = jwt.decode(token, secretkey)
//console.log(auth)
User.findOne({ username: auth.username
}, function(err, user)
{ res.json(user) }) })
app.post('/user', function(req, res) {
var user = new User({
username: req.body.username
}) bcrypt.hash(req.body.password, 10, function(err, hash) {
user.password = hash user.save(function(err, user) {
if (err) {
throw next(err)
} // res.send(201) res.json(user); }) })
})
app.listen(3000)
->This is my app.js.
"use-strict"
var express = require('express');
var router = express.Router(); // get an instance of the express Router
var morgan = require('morgan');
var bodyParser = require('body-parser');
var app = express();
/*app.use(morgan('dev'));*/
app.use('/public/app/controllers/routes', router);
app.use(bodyParser.json()); // support json encoded bodies
app.use(bodyParser.urlencoded({
extended: true
})); // support encoded bodies
app.use(require('./config/auth'))
app.use('/api/users', require('./app/controllers/api/users'))
app.use('/api/sessions', require('./app/controllers/api/sessions'))
app.use('/api/products', require('./app/controllers/api/products'))
app.use('/api/companies', require('./app/controllers/api/companies'))
app.use('/api/stockists', require('./app/controllers/api/stockists'))
app.use('/api/employees', require('./app/controllers/api/employees'))
app.use('/api/sales', require('./app/controllers/api/sales'))
app.use('/', require('./app/controllers/static'))
var port = process.env.PORT || 3000
var server = app.listen(port, function() {
console.log('App listening at the ', port);
});
require('./websockets').connect(server)
-> as i am trying to open. it is showing cannot get/. I have routed all the links correctly. but still this issue is pertaining me.
-> in my server it is showing mongodb connected and running. but whilw i open it it is showing cannot get/