A fully functioning domain model in idiomatic Ruby. This will then form the basis for building a UI and other components necessary for a full-stack implementation. This item includes a port of:

• All model objects (including immutability and equality for value objects)
• Unit tests (i.e. ported to Rspec)
• ?

Does not include infrastructure (eg. application services, async aggregate update mechanism, etc), UI or other non-model considerations.