DigitalObject model from generate scaffold (with edits)
Changed authenticity token settings to allow JSON API record create and update
Installed dry_crud gem and did 'rails generate dry_crud --tests rspec'
Change MyApp string to Archive Catalog
Toss out the views originally created by generate scaffold.
Added new SdrObject model & SdrObjects controller
Added composite_primary_keys gem
Added new SdrObjectVersion model & SdrObjectVersions controller.
Specified associations between model entities
Modified SdrObectVersion model. Refined associations.  Added validations.
Added models and controllers for remaining archive catalog tables
Enhanced Archive Catalog home page
Fixed broken model to_s methods and added comments
Modified find_entry to enable find_or_create behavior for create action.  Added comments.