Update announcements.json

announcements.json

 [
+    {"id":17,"title":"春晚时期平台关闭公告","url":"https://forum.my-card.in/t/topic/2781","created_at":"2014-01-30T10:34:06+08:00","updated_at":"2014-01-30T10:34:06+08:00"}, 
     {"id":19,"title":"寒假联合赛~IDuel专场","url":"http://www.duelcn.com/thread-60494-1-1.html","created_at":"2014-01-18T10:34:06+08:00","updated_at":"2014-01-18T10:34:06+08:00"}, 
     {"id":19,"title":"寒假联合赛~NW专场","url":"https://forum.my-card.in/t/nwbbs/2733","created_at":"2014-01-18T10:34:06+08:00","updated_at":"2014-01-18T10:34:06+08:00"},
     {"id":9,"title":"OCG新禁限卡表 从2月1日起适用 ","url":"https://forum.my-card.in/t/ocg-2014-2-1/2720","created_at":"2014-01-27T10:34:06+08:00","updated_at":"2014-03-27T10:34:06+08:00"},