odex25_standard/odex25_base/knowledge/demo/knowledge.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo noupdate="1">
    <record id="base.user_demo" model="res.users">
        <field name="groups_id" eval="[(4,ref('knowledge.group_document_user'))]" />
    </record>
</odoo>