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
If it only takes one value, why is it a generator?  Generators generate.

----- Original Message -----
> >        "description": "database password",
> >        "generate": "expression",
> >        "from": "[a-zA-Z0-9]{8}"
> > +    },
> > +    {
> > +      "name": "MYSQL_DATABASE",
> > +      "description": "database name",
> > +      "generate": "expression",
> 
> that's what i meant by the "value generator", the value generator is what you
> use if you just want to explicitly set the value.  It takes on parameter,
> the value you want to use.
> 
> 
> ---
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