title: heroku: issue importing python module
body: <p>This is my project structure:</p>
  
  <pre><code>project_name
  |___src
      |___model.py
  </code></pre>
  
  <p>On my local dev environment, I have added <code>project_name</code>'s parent directory to PYTHONPATH, so I can do <code>from project_name.src.model import func_name</code> in a file inside the project.</p>
  
  <p>But when I push the project to heroku, it pushes the contents of <code>project_name</code> inside an <code>app</code> directory, hence my imports fail.</p>
  
  <p>Is there any way to make this work on heroku?</p>