Update README.md

examples/guestbook/v1beta3/README.md

@@ -9,6 +9,7 @@ The example consists of:
 The web front end interacts with the redis master via javascript redis API calls.
 
 The v1beta3 API is not enabled by default. The kube-apiserver process needs to run with the --runtime_config=api/v1beta3 argument. Use the following command to enable it:
+````
 $sudo sed -i 's|KUBE_API_ARGS="|KUBE_API_ARGS="--runtime_config=api/v1beta3 |' /etc/kubernetes/apiserver
-
+````