Adds createFromCart and order.completed subscribers

packages/medusa-plugin-economic/src/subscribers/order.js

@@ -7,6 +7,10 @@ class OrderSubscriber {
     this.eventBus_.subscribe("order.placed", async (order) => {
       await this.economicService_.draftEconomicInvoice(order)
     })
+
+    this.eventBus_.subscribe("order.completed", async (order) => {
+      await this.economicService_.bookEconomicInvoice(order._id)
+    })
   }
 }