title: Trying to update to gem 3.0.20 and install a DevKit
body: <p>Heroku advised updating to this gem because of a security patch but it has caused me all kinds of headaches and now my local environment isn't working correctly.  They suggested doing this as a security precaution.    They suggested going into my app, changing the gemfile version and simply running 'bundle update rails'.  Here was the output:</p>
  
  <pre><code>$ bundle update rails
  Fetching source index for http://rubygems.org/
  Using rake (0.8.7)
  Using abstract (1.0.0)
  Using activesupport (3.0.20)
  Using builder (2.1.2)
  Using i18n (0.5.0)
  Using activemodel (3.0.20)
  Using erubis (2.6.6)
  Using rack (1.2.8)
  Using rack-mount (0.6.14)
  Using rack-test (0.5.7)
  Using tzinfo (0.3.37)
  Using actionpack (3.0.20)
  Using mime-types (1.21)
  Using polyglot (0.3.3)
  Using treetop (1.4.12)
  Using mail (2.2.19)
  Using actionmailer (3.0.20)
  Using arel (2.0.10)
  Using activerecord (3.0.20)
  Using activeresource (3.0.20)
  Using bundler (1.0.22)
  Installing json (1.7.7) with native extensions
  Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. 
  c:/Ruby192/bin/ruby.exe extconf.rb
  
  creating Makefile 
  make
  'make' is not recognized as an internal or external command,
  operable program or batch file. 
  
  Gem files will remain installed in c:/Ruby192/lib/ruby/gems/1.9.1/gems/json-1.7.7 for inspection.
  
  Results logged to c:/Ruby192/lib/ruby/gems/1.9.1/gems/json-1.7.7/ext/json/ext/generator/gem_make.out
  An error occured while installing json (1.7.7), and Bundler cannot continue.
  Make sure that `gem install json -v '1.7.7'` succeeds before bundling
  </code></pre>
  
  <p>Then they pointed to a thread on here of someone having a similar problem.  It involved downloading a Devkit etc.  I tried following the instructions but now everything is just broke.  I'm familiar working with Ruby on Rails but never had to install it (was already set up on my work computer) and I find it hard to believe that updating it is this difficult when the whole philosophy behind ruby on rails is simplicity.  I've got to be missing something or not using the proper resource.</p>
  
  <p>The current version of ruby on my machine is ruby 1.9.2p0 (2010-08-18) [i386-mingw32]</p>
  
  <pre><code>$rails --version
  Rails 3.0.3
  </code></pre>
  
  <p>And the DevKit I downloaded is 
  DevKit-tdm-32-4.5.2-20111229-1559-sfx.exe
  from <a href="http://rubyinstaller.org/downloads" rel="nofollow">http://rubyinstaller.org/downloads</a></p>
  
  <p>I then tried to walk through the installation steps on this site <a href="https://github.com/oneclick/rubyinstaller/wiki/Development-Kit" rel="nofollow">https://github.com/oneclick/rubyinstaller/wiki/Development-Kit</a></p>
  
  <p>It always comes back to a 'make' error or 'json' error.</p>
  
  <p>Maybe I have different versions conflicting??</p>
  
  <p>Now I get the following error when I just try to start WEBrick to run my app:</p>
  
  <pre><code>$ rails s
  c:/Ruby192/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/rubygems_integrat
  ion.rb:183:in `stub_source_index170': uninitialized constant Gem::SourceIndex (N
  ameError)
      from c:/Ruby192/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/ruby
  gems_integration.rb:303:in `stub_rubygems'
      from c:/Ruby192/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/ruby
  gems_integration.rb:246:in `replace_entrypoints'
      from c:/Ruby192/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler/runt
  ime.rb:14:in `setup'
      from c:/Ruby192/lib/ruby/gems/1.9.1/gems/bundler-1.0.22/lib/bundler.rb:1
  10:in `setup'
      from c:/rails/thumb/costrecovery/config/boot.rb:8:in `&lt;top (required)&gt;'
      from &lt;internal:lib/rubygems/custom_require&gt;:29:in `require'
      from &lt;internal:lib/rubygems/custom_require&gt;:29:in `require'
      from script/rails:5:in `&lt;main&gt;'
  </code></pre>
  
  <p>Any advice is greatly appreciated.</p>