Laravel 4.2软删除不起作用

I使用laravel 4.2.8和Eloquent ORM。当我尝试软删除时，它不起作用。它从我的数据库中删除数据。我想从逻辑上而不是从物理上删除数据。在这里我给我的代码什么我尝试

型号

use Illuminate'Auth'UserInterface;
use Illuminate'Database'Eloquent'SoftDeletingTrait;
class User extends Eloquent implements UserInterface {
    /**
     * The database table used by the model.
     *
     * @var string
     */
    protected $table = 'users';
        public $timestamps = true;
        protected $softDelete = true;
        protected $dates = ['deleted_at'];
        public static function boot()
        {
            parent::boot();
            static::creating(function($post)
            {
                $post->created_by = Auth::user()->id;
                $post->updated_by = Auth::user()->id;
            });
            static::updating(function($post)
            {
                $post->updated_by = Auth::user()->id;
            });
            static::deleting(function($post)
            {
                $post->deleted_by = Auth::user()->id;
            });
        }
}

控制器

public function destroy($id) {
        // delete
        $user = User::find($id);
        $user->delete();
        // redirect
        return Redirect::to('admin/user');
    }