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 id can just be "database"  (need to fix up the frontend stuff too, but i'll take care of that, i need to merge over changes i did for the blog)