Add hs_code_link

hs_code_link/models/__init__.py

@@ -0,0 +1,3 @@
+# -*- coding: utf-8 -*-
+
+from . import product

hs_code_link/models/product.py

@@ -0,0 +1,15 @@
+# -*- coding: utf-8 -*-
+# Copyright 2017 Camptocamp SA
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
+
+from odoo import models, fields
+
+
+class ProductTemplate(models.Model):
+    _inherit = 'product.template'
+
+    hs_code = fields.Char(
+        related='hs_code_id.hs_code',
+        readonly=True,
+        store=True,
+    )