[WIP] Add database pod and service for ruby sample app demo

- [ ] update ruby-sample-app image with MySQL connection for Sinatra app 
- [ ] change docker image URL with OpenShift official image for ruby-sample-app - https://github.com/openshift/ruby-hello-world/pull/5
I wonder if the 5 seconds is not too much here... I think doing a GET call to kubernetes does not cost us too much, so maybe I would go for 1 second instead.