function zn_add_open_graph(){
    ?>
        <div id="fb-root"></div>
        <script>(function(d, s, id) {
          var js, fjs = d.getElementsByTagName(s)[0];
          if (d.getElementById(id)) return;
          js = d.createElement(s); js.id = id;
          js.src = "//connect.facebook.net/de_DE/sdk.js#xfbml=1&version=v2.5&appId=1691176421151710";
          fjs.parentNode.insertBefore(js, fjs);
        }(document, 'script', 'facebook-jssdk'));</script>
    <?php
}