add proposal

Signed-off-by: May Zhang <may_zhang@intuit.com>

docs/proposals/self-service-notifications.md

@@ -52,6 +52,9 @@ This controller uses both the self-service configuration and the admin defined d
 
 ![img.png](images/self-service-notifications.png)
 
+In ArgoCD UI, when subscribing to notifications, user will be presented with a dropdown list of default-configuration and self-service-configuration if exists.
+Based on the selection of configurations, list of services and triggers will be shown for each respective configuration.
+
 ### Use cases
 
 Add a list of detailed use cases this enhancement intends to take care of.