stackage-server/templates/stackage-home.hamlet should have a "by category" link

I need to quickly determine which packages in the "Data Mining" or "Machine Learning" categories from hackage are in stackage.

For this, the list at http://www.stackage.org/lts-5.1 should either show the tags associated with packages (So I can use "find" in the browser), or some category-based drill-down should be supported.