Simply adding `gem 'unicorn'` or `gem 'rainbows'` to your Gemfile will give you unicorns or rainbows, I'll investigate ponies, thanks.
Just swap out ActionMailer with the `pony` gem!
This is true- but at least for Heroku deployment I always find myself digging around for the "unicorn-killer" stuff. But perhaps that's Heroku specific.
Why would you want unicorns AND ponies? unicorns are superior to ponies; adding them both would just bloat the framework.