10. 文章的发布时间的优化published_at

  // 将published_at 作为Carbon对象来chu l
    public $date = ['published_at'];

   // setTitleAttribute  设置属性
    public function setPublishedAtAttribute($date)
    {
        $this->attributes['published_at'] = Carbon::createFormFormat('Y-m-d',$date);
    }

    scopeFunction($query)  $query 查询语句
    public function scopePublished($query)
    {
        $query->where('published_at','<=',Carbon::now());
    }