fix(docs): suggest cors flag for using dashboard

Documentation/modules.md

@@ -5,7 +5,7 @@ These modules provide things like dashboards, locks and leader election.
 
 ### Dashboard
 
-An HTML dashboard can be found at `http://127.0.0.1:4001/mod/dashboard/`
+An HTML dashboard can be found at `http://127.0.0.1:4001/mod/dashboard/`. Use the `-cors='*'` flag to allow your browser to request information from the current master as it changes.
 
 ### Lock