allow showing stat in kiosk mode

templates/stat.html.tera

@@ -38,12 +38,14 @@
 	</div>
 
 <script>
+{% if personal %}
 const data = [
   {%- for p in personal %}
     { date: '{{p.date}}', km: {{p.km}} },
   {%- endfor %}
 ]
 sessionStorage.setItem('userStats', JSON.stringify(data));
+{% endif %}
 </script>
 
 <script src="/public/logbook.js"></script>