JSON to string

Changing JSON back to string in some macros from previous merge that was not released

Add product_id to test

Add product_id to the uniqueness test in stg_shopify__product_image

adding json

Merge pull request #5 from graze/adding-new-json-config

adding json

adding discount_application

adds staging for discount_application

adds discount_allocation_staging

adds staging model for discount_allocation