Revert "feat(server): deprecated the subscription module."

This reverts commit 3b79ac66ae.

packages/server/src/system/repositories/SubscriptionRepository.ts

@@ -0,0 +1,26 @@
+import SystemRepository from '@/system/repositories/SystemRepository';
+import { PlanSubscription } from '@/system/models';
+
+export default class SubscriptionRepository extends SystemRepository {
+  /**
+   * Gets the repository's model.
+   */
+  get model() {
+    return PlanSubscription.bindKnex(this.knex);
+  }
+
+  /**
+   * Retrieve subscription from a given slug in specific tenant.
+   * @param {string} slug
+   * @param {number} tenantId
+   */
+  getBySlugInTenant(slug: string, tenantId: number) {
+    const cacheKey = this.getCacheKey('getBySlugInTenant', slug, tenantId);
+
+    return this.cache.get(cacheKey, () => {
+      return PlanSubscription.query()
+        .findOne('slug', slug)
+        .where('tenant_id', tenantId);
+    });
+  }
+}