title: Rails 5 ActiveRecord Delete Duplicates
body: <p>I have a Rails 5 app. I have a table filled with URL data that is pulled in from various sources:</p>
  
  <pre><code>id     url
  1      http://google.com
  2      http://yahoo.com
  3      http://msn.com
  4      http://google.com
  5      http://yahoo.com
  6      http://askjeeves.com
  </code></pre>
  
  <p><strong>How can I remove the duplicates from this table?</strong></p>