yii migrate/up --migrationPath=@vendor/octoweb/yii2-settings/migrations

<?php
    ......
   'modules' => [
        'settings' => [
            'class' => 'octoweb\settings\Module',
        ]
    ],
    ......

?>

<?php
    ......
   'components' => [
        'setting'=>[
            'class'=>'octoweb\settings\components\SettingSite'
        ]
    ]
    ......

?>

<?=Yii::$app->setting->get('site','favicon')?>