Add info on resource for Ruby Datamapper approach.
Add info on resource for Ruby Datamapper approach.

paulrayner/ddd_sample_app_ruby,makenoisewacamayo/ddd_sample_app_ruby,paulrayner/ddd_sample_app_ruby,jbpadgett/ddd_sample_app_ruby,makenoisewacamayo/ddd_sample_app_ruby,jbpadgett/ddd_sample_app_ruby,makenoisewacamayo/ddd_sample_app_ruby,jbpadgett/ddd_sample_app_ruby