title: Wordpress Contact form 7 custom shortcodes
body: <p>Contact form 7 has some shortcodes, like [_date] to get todays date. But I want to display the date one week from now.</p>
  
  <p>So I need to create a custom shortcode to Contact form 7 that takes say [next_week] and in the recived email the correct date is displayed.</p>
  
  <p>Where and how do I create custom shortcodes to Contact form 7?</p>