<ul> {% for category in site.categories %}

{% if category[0] == page.category %}
  {% assign post_list = category[1] %}
  {%- for post in post_list -%}
    <li>
      <span>{{ post.date | date: "%Y-%m-%d" }}</span> &raquo;
      <a href="{{ post.url | relative_url }}">
        {{ post.title | escape }}
      </a>
    </li>
  {%- endfor -%}
{%- endif -%}

{% endfor %} </ul>