updating travis config

Author: Nyholm

.travis.yml

@@ -9,7 +9,9 @@ php:
 env:
   global:
     - TEST_COMMAND="composer test"
-    - SYMFONY_VERSION=2.8.*
+  - SYMFONY_VERSION=3.0.*
+  - SYMFONY_VERSION=2.8.*
+  - SYMFONY_VERSION=2.7.*
 
 matrix:
   fast_finish: true
@@ -22,7 +24,6 @@ matrix:
         - COMPOSER_FLAGS="--prefer-stable --prefer-lowest"
         - COVERAGE=true
         - TEST_COMMAND="composer test-ci"
-    - env: SYMFONY_VERSION=2.7.*
 
 before_install:
   - travis_retry composer self-update