title: Heroku: run npm install and gulp build for a Django app
body: <p>I have a Django app that I managed to deploy with Heroku. My <code>Procfile</code> file only contains : </p>
  
  <pre><code>web: gunicorn omegapp3.wsgi --log-file -
  </code></pre>
  
  <p>So when I run <code>heroku local</code> it works.</p>
  
  <p>But when I deploy with <code>heroku push master</code>, the console detects a <strong>Node app</strong> because the app has a <code>package.json</code> and then the build fails. </p>
  
  <p>What I would like to do is the following : </p>
  
  <ul>
  <li>run <code>npm install</code> to install <code>gulp</code> etc.</li>
  <li>run gulp build.</li>
  </ul>
  
  <p>Do you know how I can do that ?</p>