installing graphael-for-rails on rails 4.0.0

Question

I'm trying to install graphael-for-rails. Apparently this relies on railties 3.1, whereas my app is a rails 4.0 app and rails 4.0 relies on railties 4.0.

I'm getting the error:

  Bundler could not find compatible versions for gem "railties":
  In Gemfile:

    graphael-on-rails (>= 0) ruby depends on
      railties (~> 3.1) ruby

    rspec-rails (~> 2.14.0) ruby depends on
      railties (4.0.0)

what should I do? I don't think forcing everything to use railties 3.2 is an option, or is it? thanks for any input!

My Gemfile:

gem 'rails', '4.0.0'

gem 'acts_as_tree'
gem 'bcrypt-ruby'
gem 'cancan'
gem 'daemons'
gem 'delayed_job_active_record'
gem 'devise'
gem 'devise_ldap_authenticatable'
gem 'rails_config'
gem 'haml'
gem 'kaminari'
gem 'rest-client'
gem 'spreadsheet'
gem 'ipaddress'
gem 'state_machine'
gem 'amqp', '~> 1.3.0'
gem 'ransack'
gem 'prawn', '~> 1.1.0'
gem 'roo', '~> 1.13.2'
gem 'bootstrap-sass', '< 3.0'
gem "paranoia", "~> 2.0" # https://github.com/radar/paranoia
gem 'graphael-on-rails'

# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.2'

# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'

# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'

# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby

# Use jquery as the JavaScript library
gem 'jquery-rails'

# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'

# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 1.2'


group :development, :test do
  gem 'sqlite3', platform: :ruby
  gem 'rspec-rails', '~> 2.14.0'
  gem 'guard-rspec'
  gem 'guard-spork'
  gem 'spork'
  gem 'quiet_assets'
  gem 'ci_reporter'
  gem 'brakeman', require: false
  gem 'bullet'
  gem 'pry', '~> 0.9.10'
  gem 'pry-rails'
  gem 'pry-nav'
  gem 'fakeweb'
  gem 'spring'
  gem 'spring-commands-rspec'
  gem 'annotate'
  gem 'rails-erd'
  gem 'debugger'
  gem 'rubocop', require: false
end

group :deployment do
  gem 'capistrano', '< 3.0'
end

group :test do
  gem 'simplecov-rcov'
  gem 'factory_girl_rails'
  gem 'capybara'
  gem 'database_cleaner'
end

group :production do
  gem 'therubyracer', :platforms => :ruby
  gem 'pg', platform: :ruby
end

group :doc do
  # bundle exec rake doc:rails generates the API under doc/api.
  gem 'sdoc', require: false
end