title: How does bundler know which version of a gem to install?
body: <p>I have been using the <code>less-rails-bootstrap</code> gem from <a href="https://github.com/metaskills/less-rails-bootstrap" rel="nofollow">https://github.com/metaskills/less-rails-bootstrap</a> in my <code>rails 3.1</code> project.</p>
  
  <p>I want to upgrade to the 2.0wip version of bootstrap and I found a fork with the same name under <a href="https://github.com/sgruhier/less-rails-bootstrap" rel="nofollow">https://github.com/sgruhier/less-rails-bootstrap</a></p>
  
  <p>Both version say to install you add <code>gem 'less-rails-bootstrap'</code> to your gemfile.</p>
  
  <p>Well, how is bundler going to know which one to use?  What if 20 people had gems with the exact same name?  </p>
  
  <p>I guess the bigger question is how to I specify which gem to use?</p>