Add symfony 3.0 support

Author: makasim

.travis.yml

@@ -9,14 +9,19 @@ cache:
 matrix:
   include:
     - php: 5.5
-      env: SYMFONY_VERSION=2.7.*
-    - php: 5.6
-      env: SYMFONY_VERSION=2.7.*
+      env: SYMFONY_VERSION=2.8.*
     - php: 5.6
       env: SYMFONY_VERSION=2.8.*
     - php: 7.0
       env: SYMFONY_VERSION=2.8.*
+    - php: 5.5
+      env: SYMFONY_VERSION=3.0.*
+    - php: 5.6
+      env: SYMFONY_VERSION=3.0.*
+    - php: 7.0
+      env: SYMFONY_VERSION=3.0.*
     - php: hhvm
+      env: SYMFONY_VERSION=2.8.*
   allow_failures:
     - php: hhvm