Yii2 引入富文本编辑器 redactor 报错 [ 2.0 版本 ]

在view层：

<?= $form->field($model, 'content')->widget(\yii\redactor\widgets\Redactor::className(), [ 
    'clientOptions' => [ 
        'imageManagerJson' => ['/redactor/upload/image-json'], 
        'imageUpload' => ['/redactor/upload/image'], 
        'fileUpload' => ['/redactor/upload/file'], 
        'lang' => 'zh_cn', 
        'plugins' => ['clips', 'fontcolor','imagemanager'] 
    ] 
]) ?>