spree/spree — pull request #2931 by jdutil (2013-04-23 22:48:04+00:00)
Title: Update shipping rate cost column to default to 0.

This prevents an issue where a shipping rate can have a nil cost, which will cause Shipment#ensure_correct_adjustment to fail from a nil adjustment amount.

https://github.com/spree/spree/blob/master/core/app/models/spree/shipment.rb#L277-L278