Polymorphically adds tags to ActiveRecord models:

Usage:
class Photo < ActiveRecord::Base
  has_many_tags
end

now, photo is taggable as follows:
photo = Photo.create
photo.tag_names << "landscape"
photo.tag_names << "2013 trip"

installation:
add the following to Gemfile:
gem 'tag_bat'

then, from the command line run:
$ bundle install
$ rake tab_bat:install:migrations
$ rake db:migrate