social/social_media_tripadvisor/views/website_views.xml

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

    <record id="view_website_form_extra"
            model="ir.ui.view">
      <field name="name">website.form</field>
      <field name="model">website</field>
      <field name="inherit_id"
             ref="website.view_website_form"/>
      <field name="arch"
             type="xml">
        <field name="social_github"
               position="after">

          <field name="social_tripadvisor"
                 placeholder="http://tripadvisor.de"/>

        </field>
      </field>
    </record>

  </data>
</openerp>