Apparently. It's the only way Rails is still aware of the Postgres extension that gets created. The build fails when rake db:schema:load is used for some reason... even though the extension exists in Postgres, Rails isn't aware of it. Here's an [example build](https://github.com/discourse/discourse/blob/master/.travis.yml#L12) notice that running `echo '\dx' | psql supermarket_test` reveals that the extension is indeed installed but further down I had `spec_helper.rb` spit out if the pg_pgtrm extension is enabled, all the extensions that are enabled and the connection information. Based on that build Rails thinks pg_pgtrm is disabled and it's not included in the array that's returned from `ActiveRecord::Base.connection.extensions` but the connection information looks as expected (it's connecting to the right database).

Not to say that Discourse is the end all be all but it's worth noting that their `.travis.yml` config [runs all migrations](https://github.com/discourse/discourse/blob/master/.travis.yml#L12).