Add missing dependencyo

composer.json

@@ -20,7 +20,8 @@
         "php": ">=5.3.2",
         "friendsofsymfony/user-bundle": "1.2.*",
         "sonata-project/admin-bundle": "2.0.*",
-        "sonata-project/easy-extends-bundle": "*"
+        "sonata-project/easy-extends-bundle": "*",
+        "sonata-project/doctrine-extensions": "dev-master"
     },
     "suggest": {
         "sonata-project/doctrine-orm-admin-bundle": "2.0.*"