Update user lifecycle and add diagram

src/TermsOfUse.md

@@ -47,9 +47,14 @@ Furthermore, the user must always observe and comply with the instructions given
 
 ## § 6 User Lifecycle
 
-1. Users must log in to the JupyterHub cluster again at the latest 12 months after their last login. During this process a check is made to see whether the requirements for using the service are still met. (feedback)
-2. If the access conditions after this period are not met, the access to the cluster will be disabled. Please contact use retrieve your data before the deletion deadline (18 months inactivity).
-3. If the last activity on cluster is more than 18 ago, all stored data of the user, including the home directory will be deleted.
+1. Users must log in to the JupyterHub cluster again at the latest 12 months after their last login. During this process a check is made to see whether the access conditions for using the service are still met.
+2. If the access conditions after this period are not met, the access to the cluster will be disabled.
+3. If the last user activity on cluster is more than 12 months ago, the access to the cluster will be disabled and the user will be notified via mail about a pending deletion of account.
+4. If the last user activity on cluster is more than 18 months ago, the user account will be finally deleted including all stored data in its home directory. Shared folders are only deleted after all user accounts with access to the share have been expired.
+
+Users who have their account deactivated due to unmet access conditions can contact us to gain access to their user data within the 18 month deletion period.
+
+![User Lifecycle Diagram](./images/UserLifecycle.svg)
 
 ## § 7 Liability