update docs

Author: Angel Rey

README.md

@@ -141,6 +141,12 @@ cd ./apps/zulip
 docker compose exec -u zulip zulip /home/zulip/deployments/current/manage.py generate_realm_creation_link
 ```
 
+## For Authentik
+
+Use this url to access the admin settings.
+
+https://authentik.<your_domain>/if/flow/initial-setup/
+
 ## Available Services
 
 ### Communication