Added redis cache driver.
diff --git a/system/libraries/Cache/Cache.php b/system/libraries/Cache/Cache.php
index 2e78a66..2555550 100644
--- a/system/libraries/Cache/Cache.php
+++ b/system/libraries/Cache/Cache.php
@@ -39,7 +39,7 @@
 class CI_Cache extends CI_Driver_Library {
 
 	protected $valid_drivers 	= array(
-		'cache_apc', 'cache_file', 'cache_memcached', 'cache_dummy'
+		'cache_apc', 'cache_file', 'cache_memcached', 'cache_redis', 'cache_dummy'
 	);
 
 	protected $_cache_path		= NULL;		// Path of cache files (if file-based cache)