title: Get all available timezones
body: <p>I'm currently working on an application that is required to support multiple timezones.</p>
  
  <p>For that, I'm using the dateutil library. Now, I need a way to present the user a list of all available timezones the dateutil library supports.</p>
  
  <p>Also, is it advisable to store the tz as strings in the database like "Europe/Berlin"?</p>