What is common between Rails, Sinatra and numerous other Ruby frameworks?
They are built on top of Rack or have Rack interfaces for allowing application servers to connect to them.
A deep-dive of sorts on Rack and see what it takes to build a framework, helping us understand these better and ultimately rolling our own.
Almost anyone doing a Ruby app ends up using Rack in one way or the other without ever realising the magic and simplicity that it provides. This session should help decoding that and provide ways on writing your own frameworks.