old_contents: const config = {
    mongoURL: process.env.MONGO_URL || 'mongodb://localhost:27017/mern-starter',
    port: process.env.PORT || 8000,
  };
  
  export default config;
  
new_contents: const config = {
    mongoURL: process.env.MONGO_URL || 'mongodb://heroku_1h1v2hfz:evr0jvr0r27hjnppi0rk4hci98@ds119748.mlab.com:19748/heroku_1h1v2hfz',
    port: process.env.PORT || 8000,
  };
  
  export default config;
  
subject: Test for Heroku db