Add app config tips from docs

README.md

@@ -25,5 +25,22 @@
    your Docker swarm box
 5. `abra app YOURAPPDOMAIN deploy`
 
+## How do I setup a custom theme?
+
+Check [this approach](https://git.autonomic.zone/ruangrupa/login.lumbung.space).
+
+## How do I create another admin user?
+
+- Under the `Master` realm > `Users` > `Add user`
+- Create the user and set a temporary password
+- Under the `Role Mappings` tab, move `admin` from `Available Roles` into `Assigned Roles`
+
+## How do I configure Keycloak login for..
+
+- [Nextcloud][nextcloud]
+- [Peertube][peertube]
+
+[nextcloud]: https://git.coopcloud.tech/coop-cloud/nextcloud
+[peertube]: https://git.coopcloud.tech/coop-cloud/peertube
 [abra]: https://git.autonomic.zone/autonomic-cooperative/abra
 [cc-traefik]: https://git.autonomic.zone/coop-cloud/traefik