public function edit(){
    //引入 config.php配置文件
    $file = APP_PATH.‘Common/Conf/config.php‘;
    $config = include APP_PATH.‘Common/Conf/config.php‘;        
    $date = I(‘post.‘);
    $date = array_change_key_case($date,CASE_UPPER);
    //合并
    $config = array_merge($config,$date);
    //重写 config 文件 
    //由于是数组，在进行写入的时候，需要转换为字符串
    $str = "<?php\r\nreturn ".var_export($config,true).";\r\n?>";
    if(file_put_contents($file,$str)){
        //从哪里来回到哪里去
        $this->success(‘修改成功‘,$_SERVER[‘HTTP_REFERER‘]);
    }else{
        $this->error(‘修改失败‘);
    };
    //p($config);
}