Add subtasks restrictions and time tracking

app/Template/config/board.php

@@ -26,6 +26,9 @@
     <?= $this->formText('project_categories', $values, $errors) ?><br/>
     <p class="form-help"><?= t('Example: "Bug, Feature Request, Improvement"') ?></p>
 
+    <?= $this->formCheckbox('subtask_restriction', t('Allow only one subtask in progress at the same time for a user'), 1, $values['subtask_restriction'] == 1) ?>
+    <?= $this->formCheckbox('subtask_time_tracking', t('Enable time tracking for subtasks'), 1, $values['subtask_time_tracking'] == 1) ?>
+
     <div class="form-actions">
         <input type="submit" value="<?= t('Save') ?>" class="btn btn-blue"/>
     </div>