创建并修改好新的迁移文件之后，运行 PHP artisan migrate 报错，请问怎么解决？

各位大神求解，报错内容如下：

vagrant@homestead:~/Code/larabbs$ php artisan migrate 
In Connection.php line 664:

SQLSTATE[42S21]: Column already exists: 1060 Duplicate column name 'avatar' (SQL: alter table `users` add `avatar` varchar(255) null, add `introduction` varchar(255) null)

In Connection.php line 458:

SQLSTATE[42S21]: Column already exists: 1060 Duplicate column name 'avatar'

配置环境是Homestead+vagrant，跟教程一样