fix symfony version

Author: Grzegorz Niewiadomski

composer.json

@@ -14,7 +14,7 @@
     ],
     "require": {
         "php": ">=5.3.3",
-        "symfony/framework-bundle": "2.3|3.*",
+        "symfony/framework-bundle": "~2.3|~3.0",
         "twig/twig": "1.*"
     },
     "autoload": {