title: Learning to use Jinja2 templates, missing URL values
body: <p>I'm learning how to use Jinja2 templates (see code below). When I add an item to my form, I expect that the url will change to something like this.    </p>
  
  <pre><code>http://localhost:8080/?food=steak&amp;food=eggs&amp;food=cheese
  </code></pre>
  
  <p>However, what ends up happening is that the first <code>food</code> will have a value, but everything else will be blank. It looks something like this:</p>
  
  <pre><code>http://localhost:8080/?food=asd&amp;food=&amp;food=
  </code></pre>
  
  <p>What am I doing wrong?</p>
  
  <pre><code>&lt;form&gt;
      &lt;h2&gt;Add a Food&lt;/h2&gt;
      &lt;input type="text" name="food"&gt;
      {% if items %}
          {% for items in items %}
              &lt;input type="hidden" name="food" value="{{item}}"&gt;
          {% endfor %}
      {% endif %}
  
      &lt;button&gt;Add&lt;/button&gt;
  
      {% if items %}
          &lt;br&gt;
          &lt;br&gt;
  
          &lt;h2&gt;Shopping List&lt;/h2&gt;
          &lt;ul&gt;
              {% for item in items %}
                  &lt;li&gt;{{ item }}&lt;/li&gt;
              {% endfor %}
          &lt;/ul&gt;
      {% endif %}
   &lt;/form&gt;
  </code></pre>
  
  <p>Here is the function to render the HTML:</p>
  
  <pre><code>class MainPage(Handler):
      def get(self):
          items = self.request.get_all("food")
          self.render("shopping_list.html", items=items)
  </code></pre>