When adding new collection:

1. Create folder with _[name], and populate with .md
2. In config.yml, add under collections:
   • Set output: true
   • Set permalink: /[permalink]/
3. Enable tags for the collection:
   • Under _layouts/tags.html, class home, collect tags in the collection (see liquid example for notes and problemset)
   • Under _layouts/tags.html, class "tag-posts", show tags and links (see liquid example for notes and problemset)
4. Enable search for the collection:
   • Under assets/data/search.json, add liquid template to loop through site.[collection]