Add Refinements (Ruby Developer Experience)

[bkuhlmann]

Why

Hello. 👋 This is in response to the upcoming Ruby Developer Experience newsletter in order to share more tooling that'll enrich people's lives.

I'm the author of the Refinements gem and find this to be an amazing gem when you want want to fill in the missing gaps in Ruby core. I use this on nearly every projects which is a powerful way to enhance Ruby without monkey patching!