Heroku "Process exited with status 1"

I deployed my app to heroku fine with no problems. I was able to run heroku local web on localhost:5000 and it worked. When I went to the web dyno address, it said application error. I checked the logs for the site and it said:

 2017-05-01T02:52:30.980217+00:00 app[web.1]:     at Connection.<anonymous> (/app/node_modules/mongodb-core/lib/connection/pool.js:274:12)
 2017-05-01T02:52:30.980218+00:00 app[web.1]:     at emitTwo (events.js:106:13)
 2017-05-01T02:52:30.980218+00:00 app[web.1]:     at Socket.<anonymous> (/app/node_modules/mongodb-core/lib/connection/connection.js:177:49)
 2017-05-01T02:52:30.980218+00:00 app[web.1]:     at Connection.emit (events.js:191:7)
 2017-05-01T02:52:30.980219+00:00 app[web.1]:     at emitOne (events.js:96:13)
 2017-05-01T02:52:30.980220+00:00 app[web.1]:     at Socket.emit (events.js:188:7)
 2017-05-01T02:52:30.980221+00:00 app[web.1]:     at process._tickCallback (internal/process/next_tick.js:104:9)
 2017-05-01T02:52:31.040828+00:00 heroku[web.1]: State changed from starting to crashed
 2017-05-01T02:52:31.029211+00:00 heroku[web.1]: Process exited with status 1
 2017-05-01T02:52:40.638415+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=room111-thoughts.herokuapp.com request_id=91b591cf-3d8d-4d94-8caf-7b1b868b088b fwd="108.221.62.78" dyno= connect= service= status=503 bytes= protocol=https
 2017-05-01T02:52:41.600924+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/favicon.ico" host=room111-thoughts.herokuapp.com request_id=c8f6c2d3-dc38-4e65-9a20-581910f42b36 fwd="108.221.62.78" dyno= connect= service= status=503 bytes= protocol=https

I am using node.js and server.js (the initializing script) is as follows

// load environment variables
require('dotenv').config();

// grab our dependencies
const express    = require('express'),
  app            = express(),
  port           = process.env.PORT || 8080,
  expressLayouts = require('express-ejs-layouts'),
  mongoose       = require('mongoose'),
  bodyParser     = require('body-parser'),
  session        = require('express-session'),
  cookieParser   = require('cookie-parser'),
  flash          = require('connect-flash'),
  expressValidator = require('express-validator');

// configure our application ===================
// set sessions and cookie parser
app.use(cookieParser());
app.use(session({
  secret: process.env.SECRET, 
  cookie: { maxAge: 60000 },
  resave: false,    // forces the session to be saved back to the store
  saveUninitialized: false  // dont save unmodified
}));
app.use(flash());

// tell express where to look for static assets
app.use(express.static(__dirname + '/public'));

// set ejs as our templating engine
app.set('view engine', 'ejs');
app.use(expressLayouts);

// connect to our database
mongoose.connect(process.env.DB_URI);

// use body parser to grab info from a form
app.use(bodyParser.urlencoded({ extended: true }));
app.use(expressValidator());

// set the routes =============================
app.use(require('./app/routes'));

// start our server ===========================
app.listen(port, () => {
  console.log(`App listening on http://localhost:${port}`);
});

I don't have any idea what is happening, especially because it worked fine on localhost and deployment. Any help is appreciated.

via I am a registered user