Add more words about caching in the docs quickstart

Fixes jsocol#181

docs/index.rst

@@ -5,7 +5,7 @@ Django Ratelimit
 Project
 =======
 
-**Django Ratelimit** is a ratelimiting decorator for Django views.
+**Django Ratelimit** is a ratelimiting decorator for Django views, storing rate data in the configured `Django cache backend <https://docs.djangoproject.com/en/dev/topics/cache/>`__.
 
 .. image:: https://travis-ci.org/jsocol/django-ratelimit.png?branch=master
    :target: https://travis-ci.org/jsocol/django-ratelimit
@@ -40,6 +40,7 @@ Use as a decorator in ``views.py``:
     def secondview(request):
         # ...
 
+After activating django-ratelimit, you should ensure that your cache backend is setup to be both persistent and work across multiple deployment worker instances (for instance UWSGI workers). Read more in the Django docs on `caching <https://docs.djangoproject.com/en/dev/topics/cache/>`__.
 
 .. _PyPI: http://pypi.python.org/pypi/django-ratelimit