title: Rails - Find missing keys between different locales (.yml files)
body: <p>I have 2 locale files <strong>en.yml</strong> and <strong>pt.yml</strong>. There are some keys that exist only on <strong>pt.yml</strong> and other keys that exist only on <strong>en.yml</strong></p>
  
  <p>Is there a method or routine to list all these keys? (Just comparing the two files)</p>
  
  <p>Example output:</p>
  
  <pre><code>en.activerecord.attributes.person.hand
  pt.activerecord.models.bird
  </code></pre>
  
  <p>Obs: something other than the  <code>i18n-tasks missing</code> task.</p>