title: Could not find gem 'mysql2 (>= 0) ruby' in the gems available on this machine
body: <p><br/>
  I installed rails on my computer, made under this instruction -<a href="https://coderwall.com/p/auvm9g" rel="nofollow">https://coderwall.com/p/auvm9g</a> <br/>
  When installing a new project - rails new my_project -d mysql</p>
  
  <pre><code>    Installing mysql2 (0.3.13) 
  Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
  
      /Users/albert/.rvm/rubies/ruby-1.9.3-head/bin/ruby extconf.rb 
  checking for rb_thread_blocking_region()... yes
  checking for rb_wait_for_single_fd()... yes
  checking for rb_hash_dup()... yes
  checking for rb_intern3()... yes
  checking for mysql.h... no
  checking for mysql/mysql.h... no
  -----
  mysql.h is missing.  please check your installation of mysql and try again.
  -----
  *** extconf.rb failed ***
  Could not create Makefile due to some reason, probably lack of
  necessary libraries and/or headers.  Check the mkmf.log file for more
  details.  You may need configuration options.
  
  Provided configuration options:
      --with-opt-dir
      --with-opt-include
      --without-opt-include=${opt-dir}/include
      --with-opt-lib
      --without-opt-lib=${opt-dir}/lib
      --with-make-prog
      --without-make-prog
      --srcdir=.
      --curdir
      --ruby=/Users/albert/.rvm/rubies/ruby-1.9.3-head/bin/ruby
      --with-mysql-config
      --without-mysql-config
  
  
  Gem files will remain installed in /Users/albert/.rvm/gems/ruby-1.9.3-head@kyrgyz-tours/gems/mysql2-0.3.13 for inspection.
  Results logged to /Users/albert/.rvm/gems/ruby-1.9.3-head@kyrgyz-tours/gems/mysql2-0.3.13/ext/mysql2/gem_make.out
  
  An error occurred while installing mysql2 (0.3.13), and Bundler cannot continue.
  Make sure that `gem install mysql2 -v '0.3.13'` succeeds before bundling.
  </code></pre>
  
  <p>Thank you all! Gem mysql2 installed :)</p>