README: add delete_user, update metadata

README.md

@@ -5,13 +5,13 @@ Wiki and knowledge base for growing teams
 <!-- metadata -->
 
 * **Category**: Apps
-* **Status**:
+* **Status**: 1, alpha
 * **Image**: [outlinewiki/outline](https://hub.docker.com/r/outlinewiki/outline)
-* **Healthcheck**:
-* **Backups**:
-* **Email**:
-* **Tests**:
-* **SSO**:
+* **Healthcheck**: No
+* **Backups**: No
+* **Email**: No
+* **Tests**: No
+* **SSO**: 3 (OAuth)
 
 <!-- endmetadata -->
 
@@ -47,3 +47,13 @@ Avoid the use of quotes (`"..."`) as much as possible, the NodeJS scripts flip o
 ### Multiple users logging in & generic oauth
 
 `COMPOSE_FILE="compose.yml:compose.patch.yml"`
+
+### Deleting a user (e.g. to fix SSO weirdness)
+
+`abra app cmd YOURAPPNAME postgres delete_user <username-to-delete> <username-to-replace>`
+
+Where `<username-to-delete>` is the username of the user to be removed, and
+`<username-to-replace>` is the username of another user, to assign documents and
+revisions to (instead of deleting them).
+
+_As of 2022-03-30, this requires `abra` RC version, run `abra upgrade --rc`._