Lines to be added in /server/app.js

app.js

var cookieSession = require('cookie-session');
var passport = require('passport');
const passportSetup = require('./config/passport-setup');

var authRouter = require('./routes/auth-routes');

app.use('/auth', authRouter);

var mongoose = require("mongoose");

app.use(
  cookieSession({
    maxAge: 24 * 60 * 60 * 1000,
    keys: ["qwefgfds"]
  })
);

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

// To setup mongoose connection

mongoose.connect(process.env.MONGOLAB_URI || 'mongodb://localhost:27017/oauth-medium-test');

var db = mongoose.connection;
db.once('open', function () {
  console.log("Connection to MongoDB succesful...");
}).on('error', function (error) {
  console.log("MongoDB connection error: ", error);
});