@Whiplash174 don't think it's a problem with the hook. The warning on the startup is just an indication that the hook will be removed in the future but it works now.
Looks like the problem is with the plugin when it tries to delete the awards for the deleted user. Create an issue on the plugin github page.
I have followed the Heroku guide from the docs with no luck. Everything goes fine until I try to connect to the site when Heroku shows Application error page.
Here's Heroku's app log:
2017-03-29T21:22:03.000000+00:00 app[api]: Build succeeded
2017-03-29T21:22:23.566319+00:00 heroku[web.1]: Starting process with command `node loader.js --no-daemon`
2017-03-29T21:22:27.616058+00:00 heroku[web.1]: State changed from starting to crashed
2017-03-29T21:22:27.617327+00:00 heroku[web.1]: State changed from crashed to starting
2017-03-29T21:22:27.607752+00:00 heroku[web.1]: Process exited with status 0
2017-03-29T21:22:31.398032+00:00 heroku[web.1]: Starting process with command `node loader.js --no-daemon`
2017-03-29T21:22:36.001530+00:00 heroku[web.1]: Process exited with status 0
2017-03-29T21:22:36.003776+00:00 heroku[web.1]: State changed from starting to crashed
I'm willing to provide you any information needed.