title: Ruby version not in ruby-build list for rbenv
body: <p>I'm using Rails 4.2 and wanted to update my Ruby version as well with rbenv. </p>
  
  <p>I used Homebrew to install ruby-build and no matter how many times I try to update via <code>brew</code>, Ruby version 2.1.3 won't show when I run <code>rbenv install --list</code>. </p>