dennogumi.org-archive/_includes/for-loop-title-only-counter.html

		<ul class="side-nav">
			{% assign counter = 1 %}
			{% for post in site.posts reversed %}
				{% if post.categories contains include.list-category %}
				<li><a href="{{ site.url }}{{ post.url }}">#{{ counter }} {{ post.title }}</a></li>
				{% assign counter=counter | plus:1 %} 
				{% endif %}
			{% endfor %}
				<li>&nbsp;</li>
		</ul>