docs: Add a FAQ page (#590)

* How do I set the variable "user" or "system" for AI inference #262
changed from system to user

* added FAQ regarding user management

docs/docs/11-FAQ.md

@@ -0,0 +1,58 @@
+# Frequently Asked Questions (FAQ)
+
+## User Management
+
+### Lost password
+
+#### If you are not an administrator
+
+Administrators can reset the password of any user. Contact an administrator to reset the password for you.
+
+* Navigate to the `Admin Settings` page
+* Find the user in the `Users List`
+* In the `Actions` column, there is a button to reset the password
+* Enter a new password and press `Reset`
+* The new password is now set
+* If required, you can change your password again (so the admin does not know your password) in the `User Settings`
+
+#### If you are an administrator
+
+If you are an administrator and lost your password, you have to reset the password in the database.
+
+To reset the password:
+
+* Acquire some kind of tools that helps you to connect to the database:
+  * `sqlite3` on Linux: run `apt-get install sqlite3` (depending on your package manager)
+  * e.g. `dbeaver` on Windows
+* Shut down hoarder
+* Connect to the `db.db` database, which is located in the `data` directory you have mounted to your docker container:
+  * by e.g. running `sqlite3 db.db` (in your `data` directory)
+  * or going through e.g. the `dbeaver` UI to locate the file in the data directory and connecting to it
+* Update the password in the database by running `update user set password='$2a$10$5u40XUq/cD/TmLdCOyZ82ePENE6hpkbodJhsp7.e/BgZssUO5DDTa' where email='<YOUR_EMAIL_HERE>'` (don't forget to put your email address into the command)
+* The new password for your user is now `adminadmin`.
+* Start hoarder again
+* Log in with your email address and the password `adminadmin` and change the password to whatever you want in the `User Settings`
+
+### Adding another administrator
+
+By default, the first user to sign up gets promoted to administrator automatically.
+
+In case you want to grant those permissions to another user:
+
+* Navigate to the `Admin Settings` page
+* Find the user in the `Users List`
+* In the `Actions` column, there is a button to change the Role
+* Change the Role to `Admin`
+* Press `Change`
+* The new administrator has to log out and log in again to get the new role assigned
+
+### Adding new users, when signups are disabled
+
+Administrators can create new accounts any time:
+
+* Navigate to the `Admin Settings` page
+* Go to the `Users List`
+* Press the `Create User` Button.
+* Enter the information for the user
+* Press `create`
+* The new user can now log in