According to the docs, the [jquery-ujs Installation](https://github.com/rails/jquery-ujs#installation) is as easy as adding ``` gem 'jquery-rails', '~> 2.1' ``` to the Gemfile, and running: ``` $ bundle install ``` --- My app is running **Rails 3.0.15**, and `jquery-rails` seems to be compatible with it: > For Rails 3.0 , run [...] but when bundling `jquery-rails` 2.1, I seem to need Rails 3.1+: ``` Bundler could not find compatible versions for gem "railties": In Gemfile: jquery-rails (~> 2.1) x86-mingw32 depends on railties (< 5.0, >= 3.1.0) x86-mingw32 rails (= 3.0.15) ruby depends on railties (3.0.15) ``` What `jquery-rails` gem version is compatible with Rails 3.0? _(also asked [here](http://stackoverflow.com/q/13200129/341929))_