add 豆瓣话题 (#1665)

closes #1663

lib/router.js

@@ -214,6 +214,7 @@ router.get('/douban/book/rank/:type', require('./routes/douban/book/rank'));
 router.get('/douban/doulist/:id', require('./routes/douban/doulist'));
 router.get('/douban/explore/column/:id', require('./routes/douban/explore_column'));
 router.get('/douban/people/:userid/status', require('./routes/douban/people/status.js'));
+router.get('/douban/topic/:id/:sort?', require('./routes/douban/topic.js'));
 
 // 煎蛋
 router.get('/jandan/:sub_model', require('./routes/jandan/pic'));