Allow Coupon item_type for Order
Fix a bug where payment method is not refunded properly
Add coupons to seeds
Add coupon redemption to purchase flow spec
Add Promotion, Batch, Coupon serializers
Move /user/:id/orders to a separate service class + small style changes
Promotion is deletable when it is not active
Expect assumption in before blocks to hold true
Add promotion, batch, coupon services
Add promotion, batch, coupon service specs + bug fix
Fix a bug where a purchase can be fulfilled even payment method is insufficient
Remove nested path in favor of leaner service api
Update config.ru