Update manage-database-permissions.md with link at bottom

Added link to Principles and Identity Providers document to provide examples related to AAD authorization, as this document does not do a great job of explaining AAD authorization types.

Author: Mike-Ubezzi

articles/data-explorer/manage-database-permissions.md

@@ -68,6 +68,8 @@ Azure Data Explorer has the following roles:
     ```
 
     The output of the command shows the list of existing users and the roles they're assigned to in the database.
+    
+    For examples pertaining to Azure Active Directory and the Kusto authorization model, please see [Principles and Identity Providers](https://docs.microsoft.com/en-us/azure/kusto/management/access-control/principals-and-identity-providers)
 
 ## Next steps