fixed incorrect twitter link generation in category view

src/categories.js

@@ -31,7 +31,7 @@ var	RDB = require('./redis.js'),
 							'category_id': category_id,
 							'active_users': [],
 							'topics' : [],
-							'twitter-intent-url': 'https://twitter.com/intent/tweet?url=' + encodeURIComponent(global.config.url + 'category/' + category_id + '/' + category_slug) + '&text=' + encodeURIComponent(category_name)
+							'twitter-intent-url': 'https://twitter.com/intent/tweet?url=' + encodeURIComponent(global.config.url + 'category/' + category_slug) + '&text=' + encodeURIComponent(category_name)
 						};
 
 					function getTopics(next) {