https://world.hey.com/this.week.in.rails/testfixtures-fixture_path-deprecation-findermethods-find-support-for-composite-primary-key-values-87e6e69a

How to Introduce Composite Primary Keys in Rails - https://shopify.engineering/how-to-introduce-composite-primary-keys-in-rails
Delegated types - https://api.rubyonrails.org/classes/ActiveRecord/DelegatedType.html