main.html

<html>
  <head>
    <meta charset="utf-8"/>
    <title>User Login/Logout with datastore</title>
    <style>
ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #333;
}

li {
  float: left;
}

li a {
  display: block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

li a:hover {
  background-color: #111;
}
</style>
</head>
<body bgcolor="#E6E6FA">


    {% if user %}
    <ul>
      <li><a href="/edit">AddGPU</a></li>
      <li><a href="/search">Search</a></li>
      <li><a href="/compare">Compare</a></li>
      <li><a href="{{ url }}">Logout</a></li>
    </ul>
  <center><font size="5">  {{ welcome }} {{ user.email() }} </font><br/></center>


    <center><p><font size="6">List of gpu</font></br><center>

      {% for x in gpu_list %}
      <p><center><a href='/display?value={{ x.name }}'>{{ x.name }}</a></br></center></p>

      {% endfor %}

    <br/>


    {% else %}
    <p>Hello guest welcome to the application</p>
    you can {{ url_string }} <a href='{{ url }}'>here
    {% endif %}


  </body>
</html>