Fix typo, it wasn't executing the filtering on tags

app/controllers/application_controller.rb

@@ -321,7 +321,7 @@ class ApplicationController < ActionController::Base
                 a << object if (value.include?(object.category.id.to_s) rescue nil)
               end
               objects = a.uniq
-            when 'tag'
+            when 'tags'
               a = Array.new
               objects.each do |object|
                 object.tags.each do |tag|