pad out integer to match filename

things.md

@@ -3,6 +3,6 @@ title: All the Research Data things
 permalink: /researchdata/things/
 ---
 {% for thing in site.things %}
-- [Thing {{thing.thing}}:]({{site.baseurl}}{{thing.url}}) {{thing.title}}
+- [Thing {{thing.thing}}:]({{site.baseurl}}/thing-{{thing.thing | prepend: "0" | slice: -1,2 }}.md) {{thing.title}}
   - {{thing.description}}
 {% endfor %}