Update deployment-on-heroku.rst
`heroku python manage.py migrate` no longer necessary, since it's now run by the release process in the Procfile. Related to
@@ -33,7 +33,6 @@ Run these commands to deploy the project to Heroku:
heroku config:set PYTHONHASHSEED=random
git push heroku master
- heroku run python manage.py migrate
heroku run python manage.py check --deploy
heroku run python manage.py createsuperuser
heroku open
