title: Flask cannot change the hostname
body: <p>I am trying to use flask integrate stripe checkout. It can startup fine for default port and 127.0.0.1/localhost. I try to change server host because localhost does not allow access from the remote server. But it does not work after I change. 
  Would I know how to change it? Thanks a lot!</p>
  
  <p>details inform:</p>
  
  <blockquote>
    <p>Flask 0.12.2 Python 2.7.5 (default, May  3 2017, 07:55:04)</p>
  </blockquote>
  
  <p>My change:</p>
  
  <pre><code>app = Flask(__name__)
  app.config['SERVER_NAME'] = '*:5000'
  </code></pre>