Merge pull request #538 from timBrockman/patch-1

Update hellonode.md to address Connection refused

docs/hellonode.md

@@ -104,6 +104,8 @@ $ curl http://localhost:8080
 Hello World!
 ```
 
+**If you recieve a `Connection refused` message from Docker for Mac, ensure you are using the latest version of Docker (1.12 or later).** 
+
 Let’s now stop the container. In this example, our app was running as Docker process `2c66d0efcbd4`, which we looked up with `docker ps`:
 
 ```shell