Switch to use 1.0+ slugify filter instead

_includes/postslist.njk

@@ -4,7 +4,7 @@
     <a href="{{ post.url | url }}" class="postlist-link">{% if post.data.title %}{{ post.data.title }}{% else %}<code>{{ post.url }}</code>{% endif %}</a>
     <time class="postlist-date" datetime="{{ post.date | htmlDateString }}">{{ post.date | readableDate }}</time>
     {% for tag in post.data.tags | filterTagList %}
-      {% set tagUrl %}/tags/{{ tag | slug }}/{% endset %}
+      {% set tagUrl %}/tags/{{ tag | slugify }}/{% endset %}
       <a href="{{ tagUrl | url }}" class="post-tag">{{ tag }}</a>
     {% endfor %}
   </li>