diff --git a/README.md b/README.md
index d17eca0..d02a91c 100644
--- a/README.md
+++ b/README.md
@@ -46,7 +46,7 @@ end
 ```ruby
 class MovieTheater < ActiveRecord::Base
 
-  has_one :form, as: :formable
+  has_one :form, as: :formable, class_name: 'Formbuilder::Form'
 
 end
 ```