How long will I have to wait to use Jax if this is my Gemfile?

I went through Michael Hartl's Rails Tutorial for the second time just to get a refresher after taking some time off. I have a project idea that I really want to get to work on. I through the jax gem into my Gemfile and got an incompatibility error message. How long before I can use the jax gem within this configuration? Thanks in advance!

My Gemfile:

source 'https://rubygems.org'

gem 'rails',                   '4.2.0.beta2'
gem 'bcrypt',                  '3.1.7'
gem 'faker',                   '1.4.2'
gem 'carrierwave',             '0.10.0'
gem 'mini_magick',             '3.8.0'
gem 'fog',                     '1.23.0'
gem 'will_paginate',           '3.0.7'
gem 'bootstrap-will_paginate', '0.0.10'
gem 'bootstrap-sass',          '3.2.0.0'
gem 'sass-rails',              '5.0.0.beta1'
gem 'uglifier',                '2.5.3'
gem 'coffee-rails',            '4.0.1'
gem 'jquery-rails',            '3.1.2'
gem 'turbolinks',              '2.3.0'
gem 'jbuilder',                '2.1.3'
gem 'rails-html-sanitizer',    '1.0.1'
gem 'sdoc',                    '0.4.0', group: :doc
gem 'pg'

group :development, :test do
  gem 'byebug',      '3.4.0'
  gem 'web-console', '2.0.0.beta3'
  gem 'spring',      '1.1.3'
end

group :test do
  gem 'minitest-reporters', '1.0.5'
  gem 'mini_backtrace', '0.1.3'
  gem 'guard-minitest', '2.3.1'
end

group :production do
  gem 'rails_12factor', '0.0.2'
  gem 'unicorn',        '4.8.3'
end

# These were not suggested by the tutorial
gem 'bootstrap_form'
gem 'jax'

When I run bundle install, I get the following message:

 bundle install
Fetching gem metadata from https://rubygems.org/.........
Fetching additional metadata from https://rubygems.org/..
Resolving dependencies...
Bundler could not find compatible versions for gem "rails":
  In Gemfile:
    jax (>= 0) ruby depends on
      rails (~> 3.1.0) ruby

    rails (4.2.0.beta2)

Bundler could not find compatible versions for gem "rake":
  In Gemfile:
    jax (>= 0) ruby depends on
      rake (~> 0.8.7) ruby

    rails (= 4.2.0.beta2) ruby depends on
      railties (= 4.2.0.beta2) ruby depends on
        rake (10.3.2)

Bundler could not find compatible versions for gem "bundler":
  In Gemfile:
    jax (>= 0) ruby depends on
      bundler (~> 1.0.10) ruby

  Current Bundler version:
    bundler (1.6.3)

This Gemfile requires a different version of Bundler.
Perhaps you need to update Bundler by running `gem install bundler`?

sinisterchipmunk / jax

How long will I have to wait to use Jax if this is my Gemfile? #100