title: Flask delete routes added with add_url()
body: <p>at app init i'm dynamically loading URL's from the DB, adding them with <code>app.add_url()</code>.
  As the behavior is CMS like, my user can delete or change the url for some pages so i need to sometimes delete a mapping or reload all url mappings.</p>
  
  <p>Does anyone know a way to do this?</p>
  
  <p>Thanks</p>