Fix wrong metrics port in docs
It should be 9090.
@@ -178,7 +178,7 @@ systemctl status headscale
Verify `headscale` is available:
```shell
-curl http://127.0.0.1:8080/metrics
+curl http://127.0.0.1:9090/metrics
```
`headscale` will now run in the background and start at boot.
