breaking: rework how links database migrations are managed (#8162)

packages/modules/link-modules/integration-tests/__fixtures__/migrations.ts

@@ -0,0 +1,44 @@
+import {
+  defineJoinerConfig,
+  MedusaService,
+  model,
+  Module,
+} from "@medusajs/utils"
+
+export const User = model.define("user", {
+  id: model.id().primaryKey(),
+  name: model.text(),
+})
+
+export const Car = model.define("car", {
+  id: model.id().primaryKey(),
+  name: model.text(),
+})
+
+export const userJoinerConfig = defineJoinerConfig("User", {
+  models: [User],
+})
+
+export const carJoinerConfig = defineJoinerConfig("Car", {
+  models: [Car],
+})
+
+export class UserService extends MedusaService({ User }) {
+  constructor() {
+    super(...arguments)
+  }
+}
+
+export class CarService extends MedusaService({ Car }) {
+  constructor() {
+    super(...arguments)
+  }
+}
+
+export const UserModule = Module("User", {
+  service: UserService,
+})
+
+export const CarModule = Module("Car", {
+  service: CarService,
+})