social/mass_mailing_custom_unsubscribe/views/assets.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- © 2016 Jairo Llopis <jairo.llopis@tecnativa.com>
     License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl). -->

<openerp>
<data>

<template id="assets_frontend"
          inherit_id="website.assets_frontend">
    <xpath expr=".">
        <script type="text/javascript"
                src="/mass_mailing_custom_unsubscribe/static/src/js/require_details.js"/>
    </xpath>
</template>

</data>
</openerp>