Tests are failing on Ruby 1.9.3 since the release of jwt 1.5.3:

+ bundle exec rake db:drop db:create db:migrate
rake aborted!
SyntaxError: /usr/local/rvm/gems/ruby-1.9.3-p392@test_develop-3/gems/jwt-1.5.3/lib/jwt/verify.rb:7: unknown type of %string
      %i[verify_aud verify_expiration ...

http://ci.theforeman.org/job/test_develop/1859/