From https://once.com/writebook

app/models/user/role.rb

@@ -0,0 +1,11 @@
+module User::Role
+  extend ActiveSupport::Concern
+
+  included do
+    enum :role, %i[ member administrator ], default: :member
+  end
+
+  def can_administer?
+    administrator?
+  end
+end

app/models/user/transferable.rb

@@ -0,0 +1,15 @@
+module User::Transferable
+  extend ActiveSupport::Concern
+
+  TRANSFER_LINK_EXPIRY_DURATION = 4.hours
+
+  class_methods do
+    def find_by_transfer_id(id)
+      find_signed(id, purpose: :transfer)
+    end
+  end
+
+  def transfer_id
+    signed_id(purpose: :transfer, expires_in: TRANSFER_LINK_EXPIRY_DURATION)
+  end
+end