autoformat + document create-invite usage

Closes #3.

README.md

@@ -4,13 +4,17 @@ Chat that is simple, secure, and private.
 
 <!-- metadata -->
 
-* **Category**: Apps
-* **Status**:
-* **Image**: [`thecoopcloud/snikket-*`](https://hub.docker.com/u/thecoopcloud)
-* **Healthcheck**:
-* **Backups**:
-* **Email**:
-* **Tests**:
-* **SSO**:
+- **Category**: Apps
+- **Status**:
+- **Image**: [`thecoopcloud/snikket-*`](https://hub.docker.com/u/thecoopcloud)
+- **Healthcheck**:
+- **Backups**:
+- **Email**:
+- **Tests**:
+- **SSO**:
 
 <!-- endmetadata -->
+
+## CLI tips & tricks
+
+- _create an admin invite_: `abra run <app> snikket_server create-invite --admin --group default`