title: Add a prefix to all Flask routes
body: <p>I have a prefix that I want to add to every route.  Right now I add a constant to the route at every definition.  Is there a way to do this automatically?</p>
  
  <pre><code>PREFIX = "/abc/123"
  
  @app.route(PREFIX + "/")
  def index_page():
    return "This is a website about burritos"
  
  @app.route(PREFIX + "/about")
  def about_page():
    return "This is a website about burritos"
  </code></pre>