Update README

The 3 methods `add`,`delete` and `get_rating_for_user` demonstrated in the examples require the `request.COOKIES` to be passed using the keyword `cookies` (not as positional arguments). At least this is what the current implementation shows...
Merge branch 'patch-1' of https://github.com/mcnemesis/django-ratings
Backwards compatible Django 1.5 Custom User model support
Add custom User model support to tests.py
Merge branch 'master' of github.com:pauliuszaleckas/django-ratings2