title: Check user attributes according to his timezone
body: <p>Attributes are <code>start_time</code>,<code>end_time</code>,<code>time_zone</code></p>
  
  <p>I save user <code>time_zone</code> by using <code>ActiveSupport::TimeZone.all.names</code> dropdown.
  e.g </p>
  
  <pre><code>start_time =&gt; "09:00"
  end_time =&gt; "02:00"
  time_zone =&gt; "Samoa"
  </code></pre>
  
  <p>Now I can't understand how I check user start_time and end_time according to his timezone.I can't move further due to non understanding.</p>