enable zip extension

Author: mredolatti

.travis.yml

@@ -19,6 +19,9 @@ matrix:
 services:
   - redis-server
 
+before-install:
+  - echo "extension = zip.so" >> ~/.phpenv/versions/$(phpenv version-name)/etc/php.ini
+
 install:
   - composer install --prefer-source --no-interaction
   - composer update