feat: add custom domain per service section to readme

README.md

@@ -89,6 +89,16 @@ docker compose volume rm dns_config
 docker compose up -d
 ```
 
+### Custom Domain Per Service
+
+If you want a single service to have a custom domain you can use the `serviceDomains` label. This will override the default domain suffix:
+```yaml
+labels:
+  serviceName: my-app
+  serviceDomains: my-app.very.cool
+```
+
+The service would now be reachable at `https://my-app.very.cool` and `https://my-app.dev.local`.
 
 ### Certificate Lifetime