jdutil/spree_gift_card — pull request #17 by trappist (2013-05-13 23:14:18+00:00)
Title: Consider other credits in calculator

Without this, if the value of the gift card plus other credits (such as store_credits) exceeds the order total, you get a negative total. This resolves the problem by considering other existing credits in the calculator so that the gift card isn't fully consumed (if appropriate) and the order total ends up at 0.