feat: Re-compute the given items cost job.

feat: Optimize the architecture.

server/src/models/InventoryTransaction.js

@@ -15,4 +15,22 @@ export default class InventoryTransaction extends TenantModel {
   static get timestamps() {
     return ['createdAt', 'updatedAt'];
   }
+
+  /**
+   * Relationship mapping.
+   */
+  static get relationMappings() {
+    const Item = require('@/models/Item');
+
+    return {
+      item: {
+        relation: Model.BelongsToOneRelation,
+        modelClass: this.relationBindKnex(Item.default),
+        join: {
+          from: 'inventory_transactions.itemId',
+          to: 'items.id',
+        },
+      },
+    };
+  }
 }