Does this gem work with UUID as the primary key?

I looked into the source code, but couldn't find anything. I also tried it on a sample app, but it breaks on this line in readable_scopes.rb:

AND read_marks.user_id        = #{user.id}

It results in something like:

AND read_marks.user_id          = e61422-0e0c-4a49-9a4

Something like:

AND read_marks.user_id          = 'e61422-0e0c-4a49-9a4'

... seems to work. Any ideas?