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
eh, it looks like I misremembered the syntax.

If you just leave off the generate field, but specify the value field, that's how you define a set value.

However I would not have a philosophical or usability problem with the idea of a generator which took an input and returned an output, where in this case the output happened to exactly match the output.  It fits the semantics of the other generators.  (take input, produce output after some transformation).