update README

Author: themsaid

README.md

@@ -94,6 +94,10 @@ class AccountApproved extends Notification
 - `badge(1)`: Accepts an integer value for the badge. (iOS Only)
 - `setOption($key, $value)`: Allows you to set any value in the message payload. For more information [check here for iOS](https://pusher.com/docs/push_notifications/ios/server), [or here for Android](https://pusher.com/docs/push_notifications/android/server).
 
+### Routing a message
+
+By default the pusher "interest" messages will be sent to will be defined using the {notifiable}.{id} convention, for example `App.User.1`, however you can change this behaviour by including a `routeNotificationForPusherPushNotifications()` in the notifiable class method that returns the interest name.
+
 ## Changelog
 
 Please see [CHANGELOG](CHANGELOG.md) for more information what has changed recently.