fixbug mất ranking do khác field

application/views/backend/ajax/cms_ranking/ranking_selection_view.php

 <?php if(is_array($ranking) && count($ranking) > 0): ?>
     <option value="-1" ranking="-1">- Chọn -</option>
     <?php foreach ($ranking as $item): $ranking = isset($item['ranking']) ? $item['ranking'] : $item['order']; ?>
-        <option value="<?php echo $item['track_id']; ?>" ranking="<?php echo $item['ranking'] ?>">
+        <option value="<?php echo $item['track_id']; ?>" ranking="<?php echo $ranking ?>">
             <?php echo $ranking . '. ' . $item['name_song'] . ' (ID= '.$item['track_id'].')'; ?>
         </option>
     <?php endforeach; ?>