Update announcements.json

announcements.json

 [
+    {"id":18,"title":"游戏王竞赛联盟~周赛","url":"http://www.duelcn.com/thread-59882-1-1.html","created_at":"2013-12-01T18:55:06+08:00","updated_at":"2030-10-22T10:34:06+08:00"},
     {"id":20,"title":"提示版本不匹配的请到官网下载1.2.8-1.2.9更新包，解压到mycard目录覆盖","url":"http://downloads.mycard.90g.org/updates/mycard-update-1.2.8-1.2.9.zip","created_at":"2013-11-27T10:34:06+08:00","updated_at":"2013-11-27T10:34:06+08:00"},
     {"id":19,"title":"更新807新卡","url":"http://goo.gl/1jn7tq","created_at":"2013-11-27T10:34:06+08:00","updated_at":"2013-11-27T10:34:06+08:00"},
-    {"id":18,"title":"竞赛联盟11月周赛特别奖励","url":"http://www.duelcn.com/thread-60050-1-1.html","created_at":"2013-11-09T10:34:06+08:00","updated_at":"2013-10-22T10:34:06+08:00"},
     {"id":4,"title":"QQ群: Mycard - 萌卡(225669895)","url":"http://qun.qzone.qq.com/group#!/225669895/home","created_at":"2013-02-19T18:12:07+08:00","updated_at":"2013-02-19T07:12:08+08:00"}
 ]