title: Unable to install bundle
body: <p>I'm following the instruction on the <a href="http://www.railstutorial.org/book" rel="nofollow">Rails Tutorial Chapter 3</a>. When running the command line <code>bundle install --without production</code> I'm getting:</p>
  
  <pre><code>Bundler could not find compatible versions for gem "sprockets-rails":
  
  In snapshot (Gemfile.lock):
    sprockets-rails (2.1.3)
  
  In Gemfile:
  
  sass-rails (= 4.0.1) ruby depends on
    sprockets-rails (~&gt; 2.0.0) ruby
  </code></pre>
  
  <p>Running <code>bundle update</code> will rebuild your snapshot from scratch, using only
  the gems in your Gemfile, which may resolve the conflict.</p>
  
  <p>When running bundle update I'm getting:</p>
  
  <pre><code>An error occurred while installing nokogiri (1.6.2.1), and Bundler cannot continue.
  Make sure that `gem install nokogiri -v '1.6.2.1'` succeeds before bundling.
  </code></pre>
  
  <p>When I run <code>gem install nokogiri -v '1.6.2.1'</code> it complains:</p>
  
  <blockquote>
    <p>Building native extensions. This could take a while... Building
    nokogiri using packaged libraries. ERROR: Error installing nokogiri:
    ERROR: Failed to build gem native extension.
    /Users/yotamros/.rvm/rubies/ruby-2.1.2/bin/ruby extconf.rb Building
    nokogiri using packaged libraries. ----- libiconv is missing. please
    visit nokogiri.org/tutorials/installing_nokogiri.html for help with
    installing dependencies. ----- <strong>* extconf.rb failed *</strong></p>
  </blockquote>
  
  <p>This is my Gemfile:</p>
  
  <pre><code>source 'https://rubygems.org'
  ruby '2.1.2'
  #ruby-gemset=railstutorial_rails_4_0
  
  gem 'rails', '4.1.1'
  
  group :development, :test do
    gem 'sqlite3', '1.3.8'
    gem 'rspec-rails', '2.13.1'
  end
  
  group :test do
    gem 'selenium-webdriver', '2.35.1'
    gem 'capybara', '2.1.0'
  end
  
  gem 'sass-rails', '4.0.1'
  gem 'uglifier', '2.1.1'
  gem 'coffee-rails', '4.0.1'
  gem 'jquery-rails', '3.0.4'
  gem 'turbolinks', '1.1.1'
  gem 'jbuilder', '1.0.2'
  
  group :doc do
    gem 'sdoc', '0.3.20', require: false
  end
  
  group :production do
    gem 'pg', '0.15.1'
    gem 'rails_12factor', '0.0.2'
  end
  </code></pre>
  
  <p>Any help would be much appreciated.  </p>