add notes to create an emergency user

docs/backend/index.md

@@ -35,7 +35,7 @@ security
 sending-email
 subscribers
 traversal-acquisition
-users-groups
+users-groups/index
 vocabularies
 widgets
 workflows

docs/backend/users-groups/emergency-user.md

@@ -0,0 +1,64 @@
+---
+myst:
+  html_meta:
+    "description": "Create an emergency user"
+    "property=og:description": "Create an emergency user"
+    "property=og:title": "Create an emergency user"
+    "keywords": "Plone, users, groups, emergency user, pip, buildout"
+---
+
+(user-groups-emergency-user-label)=
+
+# Emergency user
+
+An emergency user is one that you can use to regain administrative access to a Plone site.
+If you lose the administrator password, or you inherit a project without proper documentation, you can create an emergency user.
+
+First of all, do the following steps not in a production environment!
+
+
+(user-groups-create-an-emergency-user-label)=
+
+## Create an emergency user
+
+There are two procedures to create an emergency user, depending on how you created and manage the Plone site.
+For both scenarios, the commands you run will stop the Plone site, add a new user, and start the Plone site.
+
+```{important}
+You should always stop your Plone site before adding a new user.
+```
+
+```{important}
+The new username must not be an existing one.
+Therefore you should avoid the username `admin`, but use another arbitrary name, such as `admin2`.
+```
+
+
+(user-groups-emergency-user-pip-installation-label)=
+
+### pip based Plone instance
+
+You can run the following shell commands to create an emergency user.
+
+```shell
+./venv/bin/instance stop
+./venv/bin/addzopeuser -c instance/etc/zope.conf <user> <password>
+./venv/bin/instance start
+```
+
+Now you can login with the created user.
+
+
+(user-groups-emergency-user-buildout-installation-label)=
+
+### Buildout based Plone instance
+
+With buildout and `plone.recipe.zope2instance`, you can run the following shell commands to create an emergency user.
+
+```shell
+bin/instance stop
+bin/instance adduser <user> <password>
+bin/instance start
+```
+
+Now you can login with the created user.

docs/backend/users-groups/index.md

@@ -0,0 +1,20 @@
+---
+myst:
+  html_meta:
+    "description": "Managing users and groups in Plone"
+    "property=og:description": "Managing users and groups in Plone"
+    "property=og:title": "Managing users and groups in Plone"
+    "keywords": "user, groups, Plone"
+---
+
+(backend-users-groups-label)=
+
+# Users and groups
+
+
+```{toctree}
+:caption: Users and groups
+:maxdepth: 2
+
+emergency-user
+```