add dependencies

composer.json

@@ -29,6 +29,7 @@
     },
     "require-dev": {
         "symfony/dom-crawler": "2.5",
-        "doctrine/doctrine-fixtures-bundle": "~2.2"
+        "doctrine/doctrine-fixtures-bundle": "~2.2",
+        "symfony/security": "~2.5"
     }
 }