This adapter uses the `phpredis` PHP extension, which can be found here:
https://github.com/nicolasff/phpredis

The Redis cache adapter is meant to be used through the `Cache` interface,
which abstracts away key generation, adapter instantiation and filter
implementation. This adapter does not aim to provide a full implementation of the
Redis API, but rather only a subset of its features that are useful in the context of a
semi-persistent cache.

A simple configuration of this adapter can be accomplished in `config/bootstrap/cache.php`
as follows:

{{{
Cache::config(array(
    'cache-config-name' => array(
        'adapter' => 'Redis',
        'host' => '127.0.0.1:6379'
    )
));
}}}

The 'host' key accepts a string argument in the format of ip:port where the Redis
server can be found.

This Redis adapter provides basic support for `write`, `read`, `delete`
and `clear` cache functionality, as well as allowing the first four
methods to be filtered as per the Lithium filtering system.