Adding notifications video to documentation (opf#10365)

docs/user-guide/notifications/README.md

@@ -12,9 +12,10 @@ This section will introduce in-app notifications and explain how to work with th
 
 ## Overview of in-app notifications in OpenProject
 
-
 In-app notifications are a tool to get notified about requests, changes and new assignments in OpenProject. The notifications can work as an alternative to email notification, or be used in parallel. This feature is enabled by default.
 
+<video src="https://openproject-docs.s3.eu-central-1.amazonaws.com/videos/OpenProject-In-app-notifications.mp4" type="video/mp4" controls="" style="width:100%"></video>
+
 ## Accessing in-app notifications
 
 Whenever you are getting in-app notification, a red elliptical with the number of notifications is displayed on the bell symbol on the upper right side of the OpenProject screen between the module button and the help button. (Please note, if there are more than 99 notifications, the elliptical will simply be red without a number in it).