docs: add docs for events and notifications

website/docs/events/notifications.md

@@ -0,0 +1,31 @@
+---
+title: Notifications
+---
+
+## Filtering Events
+
+Starting with authentik 0.15, you can create notification triggers, which can alert you based on the creation of certain events.
+
+Filtering is done by using the Policy Engine. You can do simple filtering using the "Event Matcher Policy" type
+
+![](./event_matcher.png)
+
+An Event has to match all configured fields, otherwise it will not match.
+
+To match events with an "Expression Policy", you can write code like so
+
+```python
+if "event" not in request.context:
+    return False
+
+return ip_address(request.context["evnet"].client_ip) in ip_network('192.0.2.0/24')
+```
+
+## Selecting who gets notified
+
+After you've create the policies to match the events you want, create a "Notification Trigger".
+
+You have to select which group the generated notification should be sent to. If left empty, the trigger will be disabled.
+
+You also have to select which transports should be used to send the Notification.
+A transport with the name "default-email-transport" is created by default. This transport will use the [global email configuration](../installation/docker-compose#email-configuration-optional-but-recommended)