Add Containable and Infusible (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 Containable and Infusible and use these gems to register and automatically inject dependencies. I mention both gems together because they are a powerful way in which leverage the power of object composition in Ruby rather than inheritance. This makes your implementation much easier to implement, test, and maintain.