Load external tasks asynchronously from task view page

app/Controller/ExternalTaskViewController.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace Kanboard\Controller;
+
+use Kanboard\Core\ExternalTask\ExternalTaskException;
+
+/**
+ * Class ExternalTaskViewController
+ *
+ * @package Kanboard\Controller
+ * @author  Frederic Guillot
+ */
+class ExternalTaskViewController extends BaseController
+{
+    public function show()
+    {
+        try {
+            $task = $this->getTask();
+            $taskProvider = $this->externalTaskManager->getProvider($task['external_provider']);
+            $externalTask = $taskProvider->retrieve($task['external_uri']);
+
+            $this->response->html($this->template->render($taskProvider->getViewTemplate(), array(
+                'task' => $task,
+                'external_task' => $externalTask,
+            )));
+        } catch (ExternalTaskException $e) {
+            $this->response->html('<div class="alert alert-error">'.$e->getMessage().'</div>');
+        }
+    }
+}