Gunicorn doesn't work
One of the changes in later versions of gunicorn includes not logging to stdout/stderr.  Add the argument --log-file=XXX, then examine that log file for what port it's running on.
I'm trying to deploy my django app on heroku. After following the steps instructed by the official document, the dyno I launched always crashes. Then I went through the whole process, and I think the problem might lie on the gunicorn part. 
Following the instruction, I set the Procfile as 'web: unicorn hellodjango.wsgi', and when I $foreman start, it only shows "21:21:07 web.1  | started with pid 77969". It didn't say where the web is launched. 
Then I tried to test whether gunicorn is working well. So I tried: "$gunicorn hellodjango.wsgi:application", it indeed doesn't work. 
I think the path is correct because in current folder there's a hellodjango folder and inside there's the file wsgi.py. 
What might be the problem?