From https://once.com/writebook

app/models/leafable.rb

@@ -0,0 +1,22 @@
+module Leafable
+  extend ActiveSupport::Concern
+
+  TYPES = %w[ Page Section Picture ]
+
+  included do
+    has_one :leaf, as: :leafable, inverse_of: :leafable, touch: true
+    has_one :book, through: :leaf
+
+    delegate :title, to: :leaf
+  end
+
+  class_methods do
+    def leafable_name
+      @leafable_name ||= ActiveModel::Name.new(self).singular.inquiry
+    end
+  end
+
+  def leafable_name
+    self.class.leafable_name
+  end
+end