Install jruby-jack gem from source

gistfile1.txt

$ sudo apt-get install maven2 # install maven2, if you don't have it
$ gem uninstall jruby-jack
$ gedit Gemfile # add: gem 'jruby-rack', '1.1.3.dev'
$ # while in my project's rails root
$ git clone https://github.com/jruby/jruby-rack.git
$ cd jruby-rack
$ bundle install
$ rake gem
$ gem install target/jruby-rack-1.1.3.dev.gem
$ cd ../
$ bundle install

$ bundle exec rake assets:precompile
$ bundle warble