Added info about Predis and PHPredis

Author: Nyholm

README.md

@@ -2,3 +2,6 @@
 [![Build Status](https://travis-ci.org/php-cache/redis-adapter.svg?branch=master)](https://travis-ci.org/php-cache/redis-adapter) [![codecov.io](https://codecov.io/github/php-cache/redis-adapter/coverage.svg?branch=master)](https://codecov.io/github/php-cache/redis-adapter?branch=master)
 
 This is a implementation for the PSR-6 for Redis cache. This implementation supports tags. 
+
+This implementation is using [Predis](https://github.com/nrk/predis). If you want an adapter with
+ [PHPRedis](https://github.com/phpredis/phpredis) you should look at our [PHPRedis adapter](https://github.com/php-cache/phpredis-adapter). 

composer.json

@@ -1,6 +1,6 @@
 {
     "name":              "cache/redis-adapter",
-    "description":       "A PSR-6 cache implementation using Redis. This implementation supports tags",
+    "description":       "A PSR-6 cache implementation using Redis (Predis). This implementation supports tags",
     "type":              "library",
     "license":           "MIT",
     "minimum-stability": "stable",
@@ -9,6 +9,7 @@
         "cache",
         "psr-6",
         "redis",
+        "predis",
         "tag"
     ],
     "homepage": "https://github.com/php-cache/redis-adapter",