Now the good part:
YOSEMITE UI KIT
I am sure you Sketch users are already screaming because this is the most comprehensively designed Yosemite UI KitDesigned exclusively for Sketch 3 and it’s FREE!
Thinking Like An App Designer
There’s more to designing mobile apps than meets the eye. The task requires a deep knowledge of devices, and it often means changing the way we think — even if that means leaving behind much of what we’ve learned from designing for the web.
Learn to build Ruby on Rails Web Apps From Design to Code