Update slides.html

Add new google form link

Author: stijnvanhoey

docs/slides.html

@@ -227,7 +227,7 @@
 
 ![:scale 100%](http://esq.h-cdn.co/assets/15/51/980x490/landscape-1450137389-john-cleese.JPG)
 
-### https://forms.gle/wYwY37f6z9j7J5iP8
+### https://forms.gle/j8zYZkUL9J5rfSrw8
 
 Please fill in the questionnaire.
 
@@ -402,4 +402,4 @@
       var slideshow = remark.create();
     </script>
   </body>
-</html>
+</html>