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
They would need to do this before/instead of running the cleanup script, so we should talk about it before telling them to run cleanup.

It would also make sense to actually illustrate it... ie tell them to run it, then tell them to list buildConfigs to show the buildConfig was removed.

or delete the pod, then show the pod is removed and the curl command no longer works.