title: Rails sql query difference between two dates more then 2 weeks
body: <p>I have a table that has 2 columns "date_from" and "date_to". I have to make a query which should return results where "date_to" - "date_from" == "2 weeks".</p>
  
  <p>Something like this:</p>
  
  <blockquote>
    <p><code>User.where('date_to - date_from == 2.weeks').</code></p>
  </blockquote>