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
Why do we have this file in the first place?

I guess we're missing tests for api/examples/*.json, the same way as we check examples/*.json.