Use string-based fields. [ci skip]

activemodel/lib/active_model/validations/validates.rb

@@ -63,7 +63,7 @@ module ActiveModel
       # and strings in shortcut form.
       #
       #   validates :email, format: /@/
-      #   validates :subscribed_to_newsletter, inclusion: [true, false]
+      #   validates :role, inclusion: %(admin contributor)
       #   validates :password, length: 6..20
       #
       # When using shortcut form, ranges and arrays are passed to your

guides/source/i18n.md

@@ -857,12 +857,12 @@ In the event you need to access nested attributes within a given model, you shou
 en:
   activerecord:
     attributes:
-      user/subscribed_to_newsletter:
-        true: "True"
-        false: "False"
+      user/role:
+        admin: "Admin"
+        contributor: "Contributor"
 ```
 
-Then `User.human_attribute_name("subscribed_to_newsletter.true")` will return "True".
+Then `User.human_attribute_name("role.admin")` will return "Admin".
 
 NOTE: If you are using a class which includes `ActiveModel` and does not inherit from `ActiveRecord::Base`, replace `activerecord` with `activemodel` in the above key paths.