{% comment %}
This will use the ordinal plugin when it's available. This is not
possible on github pages (unless built locally and pushed there).
{% endcomment %}
<p>
    <small>
        Posted by
        {% if node.email %}
            <a href="mailto:{{ node.email }}">{{ node.author }}</a>
        {% else %}
            {{ node.author }}
        {% endif %}

        {% assign ordinalize=node.date | date: "%-d" %}
        on {{ node.date | date: "%B %-d" }}<sup>{% include ordinal.html %}</sup>
        {{ node.date | date: "%Y" }}
    </small>
</p>