moderation.helpers.automoderate requires a User model instance, while the underlying code implies that it can accept user=None or HttpRequest.user

For now I had to replace
```
automoderate(donation, user=request.user)
```
with
```
            user_active = User.objects.filter(is_active=True).first()
            automoderate(donation, user=admin_active)
```

Environment:
- django-moderation==0.7.0
- python 3.7
- django 2.1
- django cms 3. 7