magic methods

This is an alternative solution to our embedded updates problem.  It assumes that the use cases where we need to accomodate an extremely simple upsert are few and can be specified.  As an example, a web signup form that captures information that crosses multiple resources (person, address, email,phone) and usually only a single instance of those types can be special cased with a simple json representation.  The server will figure out how to update the appropriate resources.