feat: Re-compute the given items cost job.

feat: Optimize the architecture.

server/src/models/InventoryCostLotTracker.js

@@ -0,0 +1,36 @@
+import { Model } from 'objection';
+import TenantModel from '@/models/TenantModel';
+
+export default class InventoryCostLotTracker extends TenantModel {
+  /**
+   * Table name
+   */
+  static get tableName() {
+    return 'inventory_cost_lot_tracker';
+  }
+
+  /**
+   * Model timestamps.
+   */
+  static get timestamps() {
+    return [];
+  }
+
+  /**
+   * Relationship mapping.
+   */
+  static get relationMappings() {
+    const Item = require('@/models/Item');
+
+    return {
+      item: {
+        relation: Model.BelongsToOneRelation,
+        modelClass: this.relationBindKnex(Item.default),
+        join: {
+          from: 'inventory_cost_lot_tracker.itemId',
+          to: 'items.id',
+        },
+      },
+    };
+  }
+}