display uuid in schedule form

scheduler/main/templates/main/schedule_form.html

@@ -69,7 +69,7 @@
             <div class="form-group">
                 <label for="id_schedule_id">{% translate 'Schedule ID' %}</label>
                 <div class="input-group">
-                    <input id="id_schedule_id" class="form-control" value="{{ object.pk }}" readonly>
+                    <input id="id_schedule_id" class="form-control" value="{{ object.uuid }}" readonly>
                     <div class="input-group-append">
                         <button type="button" class="btn btn-outline-secondary" tabindex="-1" data-clipboard="#id_schedule_id" data-animation="success">{% translate 'Copy' %}</button>
                     </div>