feat: implement support plan subscription functionality

src/modules/invoices/entities/invoice-item.entity.ts

@@ -5,7 +5,7 @@ import { Invoice } from "./invoice.entity";
 import { BaseEntity } from "../../../common/entities/base.entity";
 import { DecimalTransformer } from "../../../common/transformers/decimal.transformer";
 import { UserSubscription } from "../../subscriptions/entities/user-subscription.entity";
-
+import { UserSupportPlan } from "../../support-plans/entities/user-support-plan.entity";
 @Entity()
 export class InvoiceItem extends BaseEntity {
   @ManyToOne(() => Invoice, (invoice) => invoice.items, { onDelete: "CASCADE" })
@@ -28,4 +28,7 @@ export class InvoiceItem extends BaseEntity {
 
   @ManyToOne(() => UserSubscription, { nullable: true, onDelete: "RESTRICT" })
   subscriptionPlan: UserSubscription | null;
+
+  @ManyToOne(() => UserSupportPlan, { nullable: true, onDelete: "RESTRICT" })
+  supportPlan: UserSupportPlan | null;
 }