printing voucher link is visible only when there are vouchers to be printed

smash/web/templates/includes/subject_vouchers_box.html

@@ -41,7 +41,8 @@
                     {% endfor %}
                     </tbody>
                 </table>
-                <a href="#" data-url="{% url "web.views.mail_template_generate_for_vouchers" %}" onclick='
+                {% if subject.vouchers.all.count > 0 %}
+                    <a href="#" data-url="{% url "web.views.mail_template_generate_for_vouchers" %}" onclick='
                 var checkboxes = $(".voucher_checkbox");
                 var url = $(this).data("url")+"?voucher_id=";
 
@@ -52,6 +53,7 @@
                 }
                 this.href = url;
                 '>Print vouchers</a>
+                {% endif %}
 
             </div>
         </div>