Add Heroku support (#1)

* Create Procfile

* Create config.py

* Create runtime.txt

* Create app.json

* Add "Deploy to Heroku" button to README.md

Co-authored-by: Dash Eclipse <dashezup@disroot.org>

config.py

@@ -3,10 +3,11 @@ from os import environ
 
 if environ.get('DYNO'):
     data = json.loads(environ.get("HOOK_CONFIG"))
+    PORT = int(environ.get('PORT'))
 else:
     with open("config.json") as f:
         data = json.load(f)
+    PORT = data.get('port')
 
 BOT_TOKEN = data['bot_token']
-PORT = data.get('port')
 GH_WEBHOOKS = data['gh_webhooks']