title: app not defined error while deploying through modulus
body: <p>While trying to deploy my node app using modulus, I encounter the error message</p>
  
  <pre><code>ReferenceError: app is not defined
      at Object.&lt;anonymous&gt; (/mnt/app/index.js:1:63)
      at Module._compile (module.js:541:32)
      at Object.Module._extensions..js (module.js:550:10)
      at Module.load (module.js:458:32)
      at tryModuleLoad (module.js:417:12)
      at Function.Module._load (module.js:409:3)
      at Module.runMain (module.js:575:10)
      at run (node.js:348:7)
      at startup (node.js:140:9)
      at node.js:463:3
  </code></pre>
  
  <p>index.js:</p>
  
  <pre><code>var express = require('express');
  var app = express();
  
  app.get('/hello', function(req, res) {
      console.log("World!!");
  })
  </code></pre>
  
  <p>Express.js has been installed and added to "dependencies" in package.json</p>
  
  <pre><code>"dependencies": {
      "express": "^4.14.0"
    }
  </code></pre>
  
  <p>What could be the probable cause for the Error.</p>