updating travis config

Author: Nyholm

.travis.yml

@@ -9,6 +9,7 @@ php:
 env:
   global:
     - TEST_COMMAND="composer test"
+ matrix:
   - SYMFONY_VERSION=3.0.*
   - SYMFONY_VERSION=2.8.*
   - SYMFONY_VERSION=2.7.*
@@ -40,3 +41,6 @@ after_success:
   - if [[ "$COVERAGE" = true ]]; then wget https://scrutinizer-ci.com/ocular.phar; fi
   - if [[ "$COVERAGE" = true ]]; then php ocular.phar code-coverage:upload --format=php-clover build/coverage.xml; fi
 
+cache:
+  directories:
+    - $COMPOSER_CACHE_DIR