本节数据填充类的代码压缩了一下，删了好些行

class SeedRolesAndPermissionsData extends Migration
{
    public function up()
    {
        Permission::create(['name'=> 'manage_contents']);
        Permission::create(['name'=> 'manage_users']);
        Permission::create(['name'=> 'edit_settings']);
        Role::create(['name'=> 'Founder'])
            ->givePermissionTo('manage_contents', 'manage_users', 'edit_settings');
        Role::create(['name'=> 'Maintainer'])
            ->givePermissionTo('manage_contents');
    }

    public function down()
    {
        $tables= config('permission.table_names');
        DB::table($tables['permissions'])->delete();
        DB::table($tables['roles'])->delete();
    }
}

创建站长并授权的4行代码采用链式写法压缩成1行；删掉了unguard()和reguard()；在回滚操作里面仅仅清空了permissions表和roles表，其它几张表貌似可以连带清空（不确定）。

//下面这样的链式写法竟然也能生效！不禁想起了 jQuery
User::first()->assignRole('Founder')
            ->update([
                'name'=> 'zhaiduting',
                'email'=> 'zhaiduting@163.com',
            ]);

Laravel 5.5安装的permission版本为2.38.0，删掉了forgetCachedPermissions()没有报错