odoo/addons/hr_expense/hr_expense_data.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data noupdate="1">
        <!-- notify all employees of module installation -->
        <function model="mail.group" name="message_append_note">
            <!-- ids, subject, body, parent_id=False, type='notification', content_subtype='html' -->
            <value eval="[ref('mail.group_all_employees')]"/>
            <value>Module Expenses Management has been installed</value>
            <value>Manage your employee's expenses, with validations by employee
                manager and accountant, creation and payment of invoice.

                This module also uses the analytic accounting and is compatible
                with the invoice on timesheet module so that you will be able to
                automatically re-invoice your customer's expenses if your work
                by project.
            </value>
        </function>

        <!-- Resource: product.uom.categ -->
        <record id="cat_expense" model="product.category">
            <field name="parent_id" ref="product.product_category_0"/>
            <field name="name">Expenses</field>
        </record>

    </data>
</openerp>