old_contents: var express = require('express');
  var bodyParser = require('body-parser');
  var morgan = require('morgan');
  
  module.exports = function expressConfig(app) {
    var env = app.get('env');
  
    // standard POST request body parser
    app.use(bodyParser.urlencoded({ extended: false }));
  
    // parse JSON posts
    app.use(bodyParser.json());
  
    // HTTP request logger middleware
    app.use(morgan('combined'));
  
    if(env !== 'production'){
      app.set('port', 3000);
    }
  
  };
  
new_contents: var express = require('express');
  var bodyParser = require('body-parser');
  var morgan = require('morgan');
  
  module.exports = function expressConfig(app) {
    var env = app.get('env');
  
    // standard POST request body parser
    app.use(bodyParser.urlencoded({ extended: false }));
  
    // parse JSON posts
    app.use(bodyParser.json());
  
    // HTTP request logger middleware
    app.use(morgan('combined'));
  
    if(env !== 'production'){
      app.set('port', 3000);
    } else {
      app.set('port', process.env.PORT);
    }
  
  };
  
subject: Add process.env.PORT to expressConfig