add note that packer doesn't support windows containers

website/source/docs/builders/docker.html.md

@@ -30,6 +30,10 @@ support running on a Docker remote host_. You can learn about what
 [platforms Docker supports and how to install onto them](https://docs.docker.com/engine/installation/)
 in the Docker documentation.
 
+
+     Please note: Packer does not yet have support for Windows containers.
+
+
 ## Basic Example: Export
 
 Below is a fully functioning example. It doesn't do anything useful, since no