Add configuration of pypy3 + Django2.x

[gralance]

[johnthagen]

@gralance Can this be used with a virtual environment created with pypy3 -m venv my_venv?

I am getting the error:

    from django.core.wsgi import get_wsgi_application
ModuleNotFoundError: No module named 'django'

I only have Django installed into my venv.

[johnthagen]

To use a venv (e.g. created from pypy3 -m venv venv):

$ PYTHONPATH=/<project dir>/venv/site-packages uwsgi --ini nginx/uwsgi_pypy3.ini

See https://github.com/unbit/uwsgi/issues/869#issuecomment-489699865

[johnthagen]

@gralance FYI, your forked pypy_setup.py is probably not compatible with Python 3.7. See: https://github.com/operasoftware/uwsgi-pypy-python3/issues/1

[dholth]

You might be interested in my cffi-heavy rewrite of the pypy plugin. https://github.com/dholth/uwsgi