title: Employees permissions to add and edit only their products
body: <p>I want to set employees permisions to add and edit only their products (Prestashop 1.6.x). I know Prestashop doesn't save employees info in <code>product</code>s table, however, is it possible to make such functionality in a quick way? If I had employee ID in product table I'll be able to limit the permissions just for editing their products. But how can I add employee ID to the <code>product</code> table? Which file should I modify? And how can I add new row to <code>ps_product</code> table? </p>