Document initial administrator setup

README.md

@@ -108,12 +108,51 @@ docker compose logs -f backend
 
 # Restart the backend after a configuration change.
 docker compose restart backend
+```
 
-# Create a user.
+## Create the initial administrator
+
+The upstream sample configuration grants the `administrator` permission to
+role `0`, named `root`. These are excerpts from the configuration. Do not
+replace the complete `perms` object or `roles` list with these excerpts:
+
+```json
+"perms": {
+    "administrator": [0]
+},
+"roles": [
+    {"id": 0, "order_id": 0, "name": "root"}
+]
+```
+
+Keep this relation, or select the administrator role from your modified
+configuration. Then, create the user:
+
+```bash
 docker compose run --rm backend \
   drivershub --config /app/config/config.json setup create-user user@example.com
 ```
 
+Enter a secure password when the command prompts for it. The command returns a
+`UID`. Accept the user with that value:
+
+```bash
+docker compose run --rm backend \
+  drivershub --config /app/config/config.json setup accept-user UID
+```
+
+The command returns a separate `user ID`. Assign administrator role `0` to that
+user ID. Replace `0` with your administrator role ID if you changed the
+configuration:
+
+```bash
+docker compose run --rm backend \
+  drivershub --config /app/config/config.json setup update-roles USER_ID 0
+```
+
+Do not interchange `UID` and `USER_ID`. You can now sign in with the email
+address and password from the first command.
+
 ## Authors and license
 
 This Docker deployment is developed by Kosmos <me@kosmos.ac> and is licensed