title: What's the proper way to downgrade a gem?
body: <p>I recently installed the <a href="https://github.com/RailsApps/rails3-devise-rspec-cucumber">Rails3.1-Devise-Rspec-Cucumber Starter App</a> with the Gemfile listed below.  This created a Gemfile.lock file (relevant snippet below) that includes factory_girl 2.0.0rc3.  Unfortunately, this version of FactoryGirl is apparently <a href="https://github.com/thoughtbot/factory_girl/issues/156">completely busted</a>.</p>
  
  <p>What's the proper way to force my bundle to use factory_girl 2.0.0.rc1 instead of 2.0.0rc3?</p>
  
  <p>Gemfile:</p>
  
  <pre><code>source 'http://rubygems.org'
  gem 'rails', '3.1.0.rc4'
  gem 'mysql2'
  gem 'sass-rails', "~&gt; 3.1.0.rc"
  gem 'coffee-script'
  gem 'uglifier'
  gem 'jquery-rails'
  gem "therubyracer", "&gt;= 0.8.2"
  gem "rspec-rails", "&gt;= 2.6.1", :group =&gt; [:development, :test]
  gem "factory_girl_rails", "&gt;= 1.1.beta1", :group =&gt; :test
  gem "cucumber-rails", "&gt;= 1.0.0", :group =&gt; :test
  gem "capybara", "&gt;= 1.0.0", :group =&gt; :test
  gem "database_cleaner", "&gt;= 0.6.7", :group =&gt; :test
  gem "launchy", "&gt;= 0.4.0", :group =&gt; :test
  gem "devise", "&gt;= 1.3.4"
  </code></pre>
  
  <p>Relevant snippet of Gemfile.lock</p>
  
  <pre><code>factory_girl (2.0.0.rc3)
  factory_girl_rails (1.1.rc1)
    factory_girl (~&gt; 2.0.0.rc)
    railties (&gt;= 3.0.0)
  </code></pre>