没有找到php Symfony2 redis类

I am integrating redis in my symfony2. I used this tuts:

http://olegpuzanov.com/2015/02/01/using-redis-for-doctrine-caching-in-symfony2/

ClassNotFoundException in appDevDebugProjectContainer.php line 966: Attempted to load class "Redis" from the global namespace. Did you forget a "use" statement?

here are my configuration:

snc_redis:
# configure predis as client
clients:
    default:
        type: predis
        alias: default
        dsn: redis://localhost
    doctrine:
        type: predis
        alias: doctrine
        dsn: redis://localhost
# configure doctrine caching
doctrine:
    metadata_cache:
        client: doctrine
        entity_manager: Content
        document_manager: default
    result_cache:
        client: doctrine
        entity_manager: [Content]
    query_cache:
        client: doctrine
        entity_manager: Content

and my query:

       $query  = $this->createQueryBuilder('c')
        ->select('c.id, c.title, c.sequence, c.sequence_count, c.category_sequence, c.unique_id, c.priority, c.status, c.created_at,c.kaltura_id')
        ->addSelect('o.slug as owner')
        ->addSelect('cat.slug as category')
        ->addSelect("group_concat(m.name SEPARATOR ',') AS media")
        ->addSelect("group_concat(a.name SEPARATOR ',') AS album")
        ->innerJoin('c.content_owner', 'o')
        ->innerJoin('c.category', 'cat')
        ->leftJoin('c.media', 'm')
        ->leftJoin('c.albums', 'a')
        ->groupBy('c.id')
        ->setResultCacheDriver($predis)
        # set cache lifetime
        ->setResultCacheLifetime($cache_lifetime)

        ->getQuery()
        ->getArrayResult();`

also i registered the snc bundle in my app kernel.

please help

git clone https://github.com/phpredis/phpredis.git
cd phpredis
git checkout php7
phpize
./configure
make && make install
cd ..
rm -rf phpredis

See https://gist.github.com/hollodotme/418e9b7c6ebc358e7fda