Update documentation on how to delete disabled users

docs/faq.rst

@@ -401,6 +401,46 @@ Technical issues
 In this section we are trying to cover the most common problems our users are having.
 If your issue is not listed here, please consult issues with the `troubleshooting tag`_.
 
+.. _delete_users:
+
+How to delete users?
+````````````````````
+
+From the web administration interface, when a user is deleted, the user is only disabled. When a user is not enabled, this user:
+
+* cannot send/receive email
+* cannot access Mailu (admin/webmail)
+* cannot access the email box via pop3/imap
+
+It is not possible to delete users via the Mailu web administration interface. The main reason is to prevent email address reusage. If a user was deleted, it can be recreated and used by someone else. It is not clear that the email address has been used by someone else previously. This new user might receive emails which were meant to be received by the previous user. Disabling the user, prevents the email address to be reused by mistake.
+
+Another reason is that extra post-deletion steps are required after a user has been deleted from the Mailu database. Those additional steps are:
+
+* Delete the dovecot mailbox. If this does not happen, a new user with the same email address reuses the previous user's mailbox.
+* Delete the user from the roundcube database (not required when SnappyMail is used). If this does not happen, a new user with the same email address reuses the previous roundcube data (such as address lists, gpg keys etc).
+
+For safely deleting the user data (and possible the user as well) a script has been introduced. The scripts provides the following information
+
+* commands for deleting mailboxes of unknown users. These users were deleted from Mailu, but still have their mailbox data on the file system.
+* commands for deleting mailboxes and roundcube data for disabled users.
+* commands for deleting users from the Mailu database.
+
+Proceed as following for deleting an user:
+
+1. Disable the to-be-deleted user. This can be done via the Web Administration interface (/admin), the Mailu CLI command user-delete, or the RESTful API. Do **not** delete the user.
+2. Download .\\scripts\\purge_user.sh from the `github project`_. Or clone the Mailu github project.
+3. Copy the script purge_user.sh to the Mailu folder that contains the `docker-compose.yml` file.
+4. Run as root: purge_user.sh
+5. The script will output the commands that can be used for fully purging each disabled user. It will show the instruction for deleting the user from the
+
+   * Dovecot maildir from filesystem (all email data)
+   * Roundcube database (all data saved in roundcube)
+   * Mailu database.
+
+6. Run the commands for deleting all user data for each disabled user.
+
+.. _`github project`: https://github.com/Mailu/Mailu/
+
 Changes in .env don't propagate
 ```````````````````````````````
 

docs/webadministration.rst

@@ -313,7 +313,9 @@ This page is also accessible for domain managers. On the users page new users ca
 
 * Edit. For all available options see :ref:`the Add user page <webadministration_add_user>`.
 
-* Setting. Access the settings page of the user. See :ref:`the settings page <webadministration_settings>` for more information.
+* Delete. Disables the user. For more information on permanently deleting users, refer to the :ref:`How to delete users page<delete_users>`.
+
+* Settings. Access the settings page of the user. See :ref:`the settings page <webadministration_settings>` for more information.
 
 * Auto-reply. Access the auto-reply page of the user. See the :ref:`auto-reply page <webadministration_auto-reply>` for more information.