Compatibility with JSONAPI::Authorization (Resource Caching)

This issue is a (choose one):

• Feature request.

Checklist before submitting:

• I've searched for an existing issue.
• The feature I'm asking for is compliant with the JSON:API spec.

Description

JSONAPI::Authorization is a pundit based authorization tool that works out-of-the-box with jsonapi-resources' ActiveRecord backed resources.
The problem is with Cached Resource as it does not have a model key.

JSONAPI::Authorization's related issue https://github.com/venuu/jsonapi-authorization/issues/67

Features:

Exposing the original model into cache in CachedResourceFramgment(https://github.com/cerebris/jsonapi-resources/blob/master/lib/jsonapi/cached_response_fragment.rb#L87) would solve the problem easily – not sure about the cons.

I have a working solution in my fork so I can submit a PR If you are OK with the idea.

Start at lib/jsonapi/cached_response_fragment.rb around line 87 and review how Cached Resource currently represents the resource. Check the linked JSONAPI::Authorization issue and the reported fork solution, then determine whether exposing the original model resolves the missing model key without adverse effects. Done means Cached Resource works with JSONAPI::Authorization resource caching.