add doctrine/instantiator to composer.json

composer.json

@@ -16,7 +16,8 @@
         "jms/metadata": "~1.1",
         "jms/parser-lib": "1.*",
         "phpcollection/phpcollection": "~0.1",
-        "doctrine/annotations": "1.*"
+        "doctrine/annotations": "1.*",
+        "doctrine/instantiator": "~1.0.3"
     },
     "suggest": {
         "symfony/yaml": "Required if you'd like to serialize data to YAML format."