jack/templates/section.html

<h1>{{ section.parent.key }} >> {{ section.key }}</h1>

<ul>
    {% for year, list in section.published_articles|reverse|groupby('published_date.year') %}
    <li><b>{{ year }}</b>
        <ul>
            {% for event in list %}
            <li>{{event.title}}</li>
            {% endfor %}
        </ul>
    </li>
    {% endfor %}
</ul>