Catch ArgumentError when setting an attribute
  Will happen with rails enums if value doesn't match defined values
:nocov: directives for code that is not covered
primary_key rework

Reworks the key into primary_key
Fixes issue with JSONAPI compliance where primary keys were not always
output as `id`.
Updates to use  `primary_key` instead of `key`
Association primary_keys now from related resource
name-spaced models can now be created
Convert association `key` option to `foreign_key`

deprecate `key`
Resource getter methods to match rails model
Support primary_key option in routes and routing generated params.
Adds routing_ext to default requires
  Will no longer need to explicitly require routing_ext in routes.rb
Do not set param option on jsonapi_resource
Merge pull request #32 from cerebris/primary_key

Reworks key option into primary and foreign keys
Bump to 0.0.8
Implement basic sorting
Change .find signature to accept an options hash
Extract constructing order options to a private method