Add redisserver to travis ci recipe.

Author: Miquel Company Rodriguez

.travis.yml

@@ -1,15 +1,14 @@
 language: php
-
+services:
+  - redis-server
 php:
   - 5.3
   - 5.4
   - 5.5
   - hhvm
-
 matrix:
   allow_failures:
     - php: hhvm
-
 before_script:
   - echo "extension = redis.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
   - phpenv rehash