* Update the redis gem
Redis 4.1.1 includes https://github.com/redis/redis-rb/pull/829 which
fixing trying to connect to slaves marked as down
* Update the rainbows gem
* Update the mime-types and mime-types-data gems
* Update the webmock, rack-test and rake gems
* Update the sentry-raven gem
* Update the activesupport gem
* Update the backports gem
* Update the domain_name gem
* Update the method_source gem
