added /rkhleics/wagtailmenus

Contributed-apps-and-website-code.md

@@ -71,6 +71,7 @@ Also on Github:
 - https://github.com/gilsondev/wagtail-carousel
 - https://github.com/mope/wagtail_map
 - https://github.com/sixpearls/wagtail-menutia
+- https://github.com/rkhleics/wagtailmenus (multi-level navigation and flat menus)
 - https://github.com/infoportugal/wagtail-modeltranslation
 - https://github.com/infoportugal/wagtail-embedvideos
 - https://github.com/ababic/wagtailmodeladmin