iOS 关于推送消息的设置

app：app只需要放一个声音文件就行，没别的设置
服务器：服务器向苹果APNs服务器发送消息的时候，需要设置sound字段：

{
  aps =
  {
    alert = "message";
    sound = "sound file name.extension";
    badge = 1;
  };
}

参考文档：https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/RemoteNotificationsPG/Chapters/IPhoneOSClientImp.html#//apple_ref/doc/uid/TP40008194-CH103-SW6