Do not refresh the whole page when changing subtask status (work in progress)

app/Controller/SubtaskRestriction.php

@@ -0,0 +1,61 @@
+<?php
+
+namespace Kanboard\Controller;
+
+use Kanboard\Model\Subtask as SubtaskModel;
+
+/**
+ * Subtask Restriction
+ *
+ * @package  controller
+ * @author   Frederic Guillot
+ */
+class SubtaskRestriction extends Base
+{
+    /**
+     * Show popup
+     *
+     * @access public
+     */
+    public function popover()
+    {
+        $task = $this->getTask();
+        $subtask = $this->getSubtask();
+
+        $this->response->html($this->template->render('subtask_restriction/popover', array(
+            'status_list' => array(
+                SubtaskModel::STATUS_TODO => t('Todo'),
+                SubtaskModel::STATUS_DONE => t('Done'),
+            ),
+            'subtask_inprogress' => $this->subtask->getSubtaskInProgress($this->userSession->getId()),
+            'subtask' => $subtask,
+            'task' => $task,
+        )));
+    }
+
+    /**
+     * Change status of the in progress subtask and the other subtask
+     *
+     * @access public
+     */
+    public function update()
+    {
+        $task = $this->getTask();
+        $subtask = $this->getSubtask();
+        $values = $this->request->getValues();
+
+        // Change status of the previous "in progress" subtask
+        $this->subtask->update(array(
+            'id' => $values['id'],
+            'status' => $values['status'],
+        ));
+
+        // Set the current subtask to "in progress"
+        $this->subtask->update(array(
+            'id' => $subtask['id'],
+            'status' => SubtaskModel::STATUS_INPROGRESS,
+        ));
+
+        $this->response->redirect($this->helper->url->to('task', 'show', array('project_id' => $task['project_id'], 'task_id' => $task['id'])), true);
+    }
+}