docs: mention the contributing guide

Change-Id: I9b39d3f01f2973de6cf312e60dee8b6249e7805e
refs: #4414
diff --git a/README-dev.md b/README-dev.md
index d2cc54a..d9af4c9 100644
--- a/README-dev.md
+++ b/README-dev.md
@@ -1,6 +1,9 @@
 Notes for ndn-cxx developers
 ============================
 
+If you are new to the NDN community of software generally, read the
+[Contributor's Guide](https://github.com/named-data/NFD/blob/master/CONTRIBUTING.md).
+
 Code style
 ----------