CartoDB/cartodb — pull request #308 by strk (2013-12-03 11:51:06+00:00)
Title: Purge varnish items with "cdb_tablemetadata" channel on table update

Closes #296

Ensures that queries against CDB_TableMetadata for "last_updated"
(for example from Windshaft-CartoDB) are correctly invalidated.

You need to run bundle exec rake cartodb:db:load_functions to upgrade,
as already noted in the UPGRADE file.