Singularizeandcapitalizepolymorphictypes

Singularizing polymorphic association types allows you to use plural or singular
type values in your requests as allowed by JSON API.

Because ActiveRecord calls #constantize on the polymorphic association type
when you use the hash to create a new model, you must capitalize the type to
avoid a NameError.

该提问来源于开源项目：rails-api/active_model_serializers