Add database pod and service for ruby sample app demo

- [x] update ruby-sample-app image with MySQL connection for Sinatra app 
- [x] change docker image URL with OpenShift official image for ruby-sample-app - https://github.com/openshift/ruby-hello-world/pull/5
This is going to remove all the containers on their host, that might not be a good idea if they have stopped containers they were using for other things.  (it's bad enough we kill all running containers rather than just our particular containers).  So I don't think we want to do this.