ActiveRecord::AuxTable -> HasAuxTable

design_document.md

@@ -90,7 +90,7 @@ CREATE INDEX idx_plane_aux_wingspan ON plane_aux(wingspan);
 ```ruby
 class Vehicle < ActiveRecord::Base
   # Enable auxiliary table support
-  include ActiveRecord::AuxTable
+  include HasAuxTable
 end
 
 class Car < Vehicle
@@ -235,7 +235,7 @@ CREATE TABLE plane_aux (
 
 ```ruby
 class Vehicle < ActiveRecord::Base
-  include ActiveRecord::AuxTable
+  include HasAuxTable
 end
 
 class Car < Vehicle