Add namespace to kubectl create command

docs/ui.md

@@ -6,8 +6,8 @@ By default, the Kubernetes UI is deployed as a cluster addon. To access it, visi
 
 If you find that you're not able to access the UI, it may be because the kube-ui service has not been started on your cluster. In that case, you can start it manually with:
 ```sh
-kubectl create -f cluster/addons/kube-ui/kube-ui-rc.yaml
-kubectl create -f cluster/addons/kube-ui/kube-ui-svc.yaml
+kubectl create -f cluster/addons/kube-ui/kube-ui-rc.yaml --namespace=kube-system
+kubectl create -f cluster/addons/kube-ui/kube-ui-svc.yaml --namespace=kube-system
 ```
 Normally, this should be taken care of automatically by the [`kube-addons.sh`](../cluster/saltbase/salt/kube-addons/kube-addons.sh) script that runs on the master.