Replaces MongoDB support with PostgreSQL (#151)

- All schemas have been rewritten to a relational model
- All services have been rewritten to accommodate the new data model
- Adds idempotency keys to core endpoints allowing you to retry requests with no additional side effects
- Adds staged jobs to avoid putting jobs in the queue when transactions abort
- Adds atomic transactions to all methods with access to the data layer

Co-authored-by: Oliver Windall Juhl <oliver@mrbltech.com>

packages/medusa-plugin-sendgrid/src/services/sendgrid.js

@@ -37,8 +37,7 @@ class SendGridService extends BaseService {
         templateId = this.options_.gift_card_created_template
         data = {
           ...data,
-          display_value:
-            data.giftcard.discount_rule.value * (1 + data.tax_rate),
+          display_value: data.giftcard.rule.value * (1 + data.tax_rate),
         }
         break
       case "order.placed":