Clarify relationship between Moby and Docker.

Signed-off-by: Luke Marsden <me@lukemarsden.net>

README.md

@@ -1,3 +1,5 @@
+### Docker users, see [Moby and Docker](https://mobyproject.org/#moby-and-docker) to clarify the relationship between the projects
+
 ### Docker maintainers and contributors, see [Transitioning to Moby](#transitioning-to-moby) for more details
 
 The Moby Project