title: add an extra column on Tax Report of odoo 10
body: <p>I need an extra column on odoo tax report. Currently there are two columns <strong>Net</strong> and <strong>Tax</strong>. I need to add a column named <strong>Gross</strong>. This view isn't like other qweb views and not getting it. Screenshot:</p>
  
  <p><a href="https://i.stack.imgur.com/fqJEw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/fqJEw.png" alt="enter image description here"></a></p>
  
  <p>The module is <strong>account_reports</strong> and the file which is generating the report I think is <strong>account_generic_tax_report</strong>.</p>
  
  <p>It would be great if anyone can suggest me what to do.</p>
  
  <p>Regards.</p>