[Fixed]-Upgrading to Django1.8 – invalid related_name for field

Try deleting and re-generating your migrations with manage.py makemigrations <appname> for each app.

I had troubles with migrations after upgrading too. If wiping your whole DB and repopulating it from a scratch is an option, try this (after cleaning the DB):
1) run ./manage.py makemigrations app_name for each app
2) run ./manage.py migrate
3) run ./manage.py syncdb