Add BundledSerializer
Update README
Rename ResourceSerializer to ServiceResourceSerializer
Add service resource base class
Remove GET /users/:id/addresses and GET /users/:id/payment_methods
Return user for POST /users/:id/payment_methods and POST /users/:id/addresses
Add endpoints to retrieve user transactions
Eager load models in development
Update service resource base class
Add service resource models
Return code, used, used_by, used_at in coupon response
Return created_at and updated_at in all serializers
Remove order_ids from purchase serializer