title: Ruby - ERROR_Can't convert nil into an exact number
body: <p>I try  to make that, in the controller ... </p>
  
  <pre><code>raw_counter_reset_date = REDIS.hget(params[:id], 'overquota_reset_at')
  @counter_reset_date = Time.at(raw_counter_reset_date)
  </code></pre>
  
  <p>But when I want lauch application, I have this error :</p>
  
  <pre><code>can't convert nil into an exact number
  </code></pre>
  
  <p>I know that <code>@counter_reset_date = Time.at(1364046539)</code> works with numbers, but I would that the application take the timestamp date in a database and convert in date on my web-page.</p>
  
  <p>I hope to have been understandable, and thank you in advance for your help.</p>