DOCSP-23337 users and roles not synched (#55)

* DOCSP-23337 users and roles not synched

* Review feedback

* Review feedback

Author: Dave Cuthbert

source/reference/mongosync.txt

@@ -121,6 +121,14 @@ Behavior
 
 .. _c2c-mongosync-config:
 
+Cluster Independence
+~~~~~~~~~~~~~~~~~~~~
+
+``mongosync`` synchronizes collection data between a source cluster and
+destination cluster. ``mongosync`` does not synchronize :ref:`users
+<users>` or :ref:`roles <built-in-roles>`. As a result, you can create
+users with different access permissions on each cluster.
+
 Configuration File
 ~~~~~~~~~~~~~~~~~~