test php7 on travis.

Author: vagrant

.travis.yml

@@ -2,10 +2,15 @@ language: php
 
 php:
   - 5.5
+  - 5.6
+  - hhvm
+  - nightly
 
 sudo: false
 
-services: mongodb
+matrix:
+  allow_failures:
+    - php: hhvm
 
 before_install:
     - composer self-update