title: heroku error PG::Error: ERROR: function strftime(unknown, timestamp without time zone) does not exist
body: <p>I have following sql in my controller:</p>
  
  <pre><code>@tot_expense = Expense.where("strftime('%m', created_at) + 0 = ?", Time.now.strftime("%m").to_i).sum("amount")
  </code></pre>
  
  <p>This works fine in my development environment. But after deploying in heroku it gives me the below error while saving the record.</p>
  
  <blockquote>
    <p>PG::Error: ERROR:  function strftime(unknown, timestamp without time
    zone) does not exist</p>
  </blockquote>
  
  <p>I have uncommented 
  <code>config.time_zone = 'UTC'</code> in my <code>config/application.rb</code> file but it didnt work.</p>