title: Heroku Gunicorn Procfile
body: <p>I have a hard time finding documentation for creating Procfiles using flask with gunicorn and Heroku. Somewhere I found that the syntax is:
  <code>web: gunicorn my_folder.my_module:app</code>. But I can't make it work. It only works for me when my python script: <code>hello.py</code> is in the root folder of the app. When I put it in a subfolder called app and create a Procfile: <code>web: gunicorn app.hello:app</code> it doesn't work. Only when I use <code>web: gunicorn hello:app</code> and my python script is in the root folder. Can someone explain me the proper syntax of Procfiles for gunicorn on Heroku, and how to make it work when the python script is in a subfolder?</p>