Update index.rst

Add the documentation of Redis cluster mode.

docs/index.rst

@@ -544,4 +544,82 @@ Relevant configuration values
 SpreadSASLMemcachedCache
 ````````````````````````
 
-Set ``CACHE_TYPE`` to ``spreadsaslmemcached
+Set ``CACHE_TYPE`` to ``spreadsaslmemcached`` to use this type.
+
+Same as SASLMemcachedCache however, it has the ablity to spread value across
+multiple keys if it is bigger than the memcached treshold which by
+default is 1M. Uses pickle.
+
+.. versionadded:: 0.11
+
+.. versionchanged::  1.1.0
+    Renamed ``spreadsaslmemcachedcache`` to ``spreadsaslmemcached`` for
+    the sake of consistency.
+
+
+Custom Cache Backends
+---------------------
+
+You are able to easily add your own custom cache backends by exposing a function
+that can instantiate and return a cache object. ``CACHE_TYPE`` will be the
+import string to your custom function. It should expect to receive three
+arguments.
+
+* ``app``
+* ``args``
+* ``kwargs``
+
+Your custom cache object must also subclass the
+:class:`flask_caching.backends.cache.BaseCache` class. Flask-Caching will make sure
+that ``threshold`` is already included in the kwargs options dictionary since
+it is common to all BaseCache classes.
+
+An example Redis cache implementation::
+
+    #: the_app/custom.py
+    class RedisCache(BaseCache):
+        def __init__(self, servers, default_timeout=500):
+            pass
+
+    def redis(app, config, args, kwargs):
+       args.append(app.config['REDIS_SERVERS'])
+       return RedisCache(*args, **kwargs)
+
+With this example, your ``CACHE_TYPE`` might be ``the_app.custom.redis``
+
+An example PylibMC cache implementation to change binary setting and provide
+username/password if SASL is enabled on the library::
+
+    #: the_app/custom.py
+    def pylibmccache(app, config, args, kwargs):
+        return pylibmc.Client(servers=config['CACHE_MEMCACHED_SERVERS'],
+                              username=config['CACHE_MEMCACHED_USERNAME'],
+                              password=config['CACHE_MEMCACHED_PASSWORD'],
+                              binary=True)
+
+With this example, your ``CACHE_TYPE`` might be ``the_app.custom.pylibmccache``
+
+
+API
+---
+
+.. toctree::
+   :maxdepth: 2
+
+   api
+
+
+Additional Information
+----------------------
+
+.. toctree::
+   :maxdepth: 2
+
+   changelog
+   license
+
+* :ref:`search`
+
+
+.. _Flask: http://flask.pocoo.org/
+.. _werkzeug: http://werkzeug.pocoo.org/