docs: Update documentation and Doxygen documentation generation
diff --git a/helper/ndn-app-helper.h b/helper/ndn-app-helper.h
index 94d1046..e559260 100644
--- a/helper/ndn-app-helper.h
+++ b/helper/ndn-app-helper.h
@@ -31,6 +31,7 @@
 namespace ndn {
 
 /**
+ * @ingroup ndn-helpers
  * \brief A helper to make it easier to instantiate an ns3::NdnConsumer Application
  * on a set of nodes.
  */