title: Set ruby version in Gemfile
body: <p>I can set ruby version in <code>Gemfile</code> as follows:</p>
  
  <pre><code>ruby '2.0.0'
  </code></pre>
  
  <p>But what if I want to have a particular version as <code>2.0.0-p353</code>?</p>
  
  <p>When I add it to <code>Gemfile</code>, I get:</p>
  
  <pre><code>Your Ruby version is 2.0.0, but your `Gemfile` specified 2.0.0-p353
  </code></pre>
  
  <p>Is it even possible to set a particular version?</p>