odoo/bin/addons/base/base_demo.xml

<?xml version="1.0" encoding="utf-8"?>
<terp>
    <data noupdate="1">
        <record id="user_demo" model="res.users">
            <field name="login">demo</field>
            <field name="password">demo</field>
            <field name="name">Demo User</field>
            <field name="signature">Fabien Pinckaers</field>
            <field name="action_id" ref="action_menu_admin"/>
            <field name="menu_id" ref="action_menu_admin"/>
            <field name="address_id" ref="main_address"/>
            <field name="company_id" ref="main_company"/>
            <field name="groups_id" eval="('base.group_user')"/> 
        </record>
    </data>
</terp>