How can I modify Procfile to run Gunicorn process in a non-standard folder on Heroku?

I'm new to heroku and gunicorn so I'm not sure how this works. But I've done some searching and I think I'm close to deploying my Django app (1.5.1). So I know I need a Procfile which has

web: gunicorn app.wsgi

Because my directories are a bit different. I can't run gunicorn in the root directory

app_project
    requirements/
    contributors/
    app/
        app/
            settings/
            wsgi.py
        # Normally Procfile goes here
    Procfile

Normally app/ would be the root directory, but I decided to structure my folders this way to separate my django app from some other things. Since I have to put the Procfile in the root directory for heroku to recognize it, what should I put in the Procfile and/or what parameters should I place in the gunicorn command?

Note:

web: gunicorn app.wsgi # won't work because Procfile is in a directory above
                       # I also want to keep the directories as is
                       # I also don't want to create a secondary git inside the app folder just for heroku
web: gunicorn app.app.wsgi # won't work because I don't want to convert the folder into a python module

Solution 1:

Try:

web: gunicorn --pythonpath app app.wsgi

Solution 2:

As @Graham Dumpleton stated in his answer, the OP's problem could be solved by modifying his Procfile to the following:

web: gunicorn --pythonpath app app.wsgi

Why this works:

• Remember, that the Procfile is simply used by Heroku to start processes. In this case, gunicorn processes.
• Gunicorn's --pythonpath argument allows you to dynamically attach a directory to the list of directories that the Python runtime searches for when do module look-ups.
• By adding --pythonpath app to the gunicorn command, the interpreter was basically told 'look inside of the app directory for a package (also) called app which contains a module called wsgi.`

The generic names of the folders in the OP's question can obscure the syntax of the command, which is as follows: gunicorn --pythonpath <directory_containing_package> <package>.<module>

More Info:
Gunicorn Documentation