title: An error occurred while installing mysql2 (0.3.11)
body: <p>I am a rails  beginner,and I get a demo from <a href="https://github.com/rubytaiwan/jobs.ruby.tw" rel="noreferrer">https://github.com/rubytaiwan/jobs.ruby.tw</a></p>
  
  <p>but when I try to run this demo,I got an error.</p>
  
  <p>I run follow</p>
  
  <pre><code>bundle
  </code></pre>
  
  <p>I got the error</p>
  
  <pre><code>An error occurred while installing mysql2 (0.3.11), and Bundler cannot continue.
  Make sure that `gem install mysql2 -v '0.3.11'` succeeds before bundling.
  </code></pre>
  
  <p>but I can sure I have install mysql2</p>
  
  <p>and the <code>Gemfile</code> is </p>
  
  <pre><code>source 'https://rubygems.org'
  ruby "1.9.3"
  
  gem 'rails', '~&gt; 3.2.12'
  
  group :assets do
    gem 'sass-rails',   '~&gt; 3.2.3'
    gem 'coffee-rails', '~&gt; 3.2.1'
  
    # See https://github.com/sstephenson/execjs#readme for more supported runtimes
    gem 'therubyracer', :platforms =&gt; :ruby
  
    gem 'uglifier', '&gt;= 1.0.3'
  end
  
  # Bundle edge Rails instead:
  # gem 'rails', :git =&gt; 'git://github.com/rails/rails.git'
  
  gem 'devise', '~&gt;2.1.3'
  gem 'mysql2'
  
  gem "babosa"
  gem "rails_autolink"
  
  gem "settingslogic"
  gem "seo_helper"
  gem 'open_graph_helper'
  gem 'google_plus_helper'
  
  gem 'exception_notification'
  
  gem "mobile-fu"
  
  gem 'capistrano', :group =&gt; "development"
  
  gem 'rake', :group =&gt; :test
  
  group :development do
    gem "capistrano"
    gem "magic_encoding"
    gem "annotate"
  end
  
  group :test, :development do
    gem "rspec"
    gem "rspec-rails"
    gem "simplecov"
    gem "capybara"
  end
  </code></pre>
  
  <p>then I try to comment this row:</p>
  
  <pre><code>gem 'mysql2'
  </code></pre>
  
  <p>but I still got the error.
  so I do not know why this error occurs</p>