Fixed backticks used instead of single quotes. (#531)

Author: danielmorell

src/panels/UserPanel.php

@@ -237,7 +237,7 @@ public function save()
 
         try {
 
-            $authManager = Instance::ensure($this->module->authManager, `\yii\rbac\BaseManager`);
+            $authManager = Instance::ensure($this->module->authManager, '\yii\rbac\BaseManager');
 
             if ($authManager instanceof \yii\rbac\ManagerInterface) {
                 $roles = ArrayHelper::toArray($authManager->getRolesByUser($this->getUser()->id));