init common and customize

app_common/models/res_users.py

@@ -0,0 +1,10 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import api, fields, models, tools,  _
+
+
+class ResUsers(models.Model):
+    _inherit = 'res.users'
+
+    login = fields.Char(index=True)