Clarify admin bootstrap steps

POSTINSTALL.md

@@ -23,7 +23,7 @@ The installer now asks for dedicated hostnames for the Auth/Accounts/Cast/Albums
 
 ## Administration
 
-- Use the bundled CLI from the Cloudron web terminal (CLI state lives in `/app/data/cli-data`). On a new deployment initialise it once:
+- Use the bundled CLI from the Cloudron web terminal (CLI state lives in `/app/data/cli-data`). On a new deployment initialise it once (this seeds the CLI config, whitelists an admin email, and resets the CLI DB):
   ```bash
   # from the Cloudron terminal, logged in as root
   cat <<'EOF' >/cli-data/config.yaml
@@ -34,6 +34,15 @@ log:
 EOF
   mkdir -p /cli-data/export
   chown cloudron:cloudron /cli-data /cli-data/config.yaml /cli-data/export
+  cat <<'EOF' >/app/data/config/museum.override.yaml
+internal:
+  super-admins:
+    - admin@example.com
+EOF
+  rm -f /cli-data/ente-cli.db
+  chown cloudron:cloudron /app/data/config/museum.override.yaml
+
+  cloudron restart --app <your-app-domain>
 
   # store your account (enter the OTP emailed to you)
   sudo -u cloudron ente account add