freerunningtech/spree — pull request #3 by miyazawadegica (2013-12-19 07:56:48+00:00)
Title: Remove only_one_promotion_per_product validate form 

promotion/rules/product.rb.

Because we would like to create multi coupons against same product.
But, currently we can not.So, remove its validation.
For remove it, I refered to the following pull request.

[Reference]
https://github.com/spree/spree/pull/1984