fixes forking

if there are no tags just return

src/topics/tags.js

@@ -9,7 +9,10 @@ var async = require('async'),
 module.exports = function(Topics) {
 
 	Topics.createTags = function(tags, tid, timestamp, callback) {
-		if(Array.isArray(tags)) {
+		if (!Array.isArray(tags) || !tags.length) {
+			return callback();
+		}
+
 		tags = tags.slice(0, meta.config.tagsPerTopic || 5);
 
 		async.each(tags, function(tag, next) {
@@ -27,7 +30,6 @@ module.exports = function(Topics) {
 				next(err);
 			});
 		}, callback);
-		}
 	};
 
 	function cleanUpTag(tag) {