odoo-usability/product_manager_group/security/product_security.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>

<record id="group_product_manager" model="res.groups">
    <field name="name">Product Manager</field>
    <field name="users" eval="[(4, ref('base.user_root')), (4, ref('base.user_admin'))]"/>
</record>

</odoo>