diff --git a/app/models/tag.rb b/app/models/tag.rb
index 6ddc6475b..0a9e6b0aa 100644
--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@@ -76,7 +76,7 @@ class Tag < ActiveRecord::Base
         end
       end
 
-      def categories_for(tag_names, options)
+      def categories_for(tag_names, options = {})
         Array(tag_names).inject({}) do |hash, tag_name|
           hash[tag_name] = category_for(tag_name, options)
           hash