Update README.md

Author: Micha Hernandez van Leuffen

Diff for: README.md

@@ -2,8 +2,10 @@ Node.js sample application for wercker built with Express
 
 Uses the default Node.js [Docker container](https://registry.hub.docker.com/u/library/node/) from the Docker Hub.
 
+Note: this sample application only runs on the Ewok stack on wercker
+
 [![wercker status](https://app.wercker.com/status/7b1a402dd00d57fc9abddf9eb5161675/s "wercker status")](https://app.wercker.com/project/bykey/7b1a402dd00d57fc9abddf9eb5161675)
 
 ---
 Sign up for wercker [here](http://wercker.com)
-Learn more on our [dev center](http://devcenter.wercker.com)
+Learn more on our [dev center](http://devcenter.wercker.com)