- https://www.amazon.com/Well-Grounded-Rubyist-David-Black/dp/1617291692
- https://www.amazon.com/Practical-Object-Oriented-Design-Ruby-Addison-Wesley-ebook/dp/B00BXU85JO
- https://www.amazon.com/Eloquent-Ruby-Addison-Wesley-Professional/dp/0321584104 (a little old but probably still good)
- https://www.amazon.com/Design-Patterns-Ruby-Russ-Olsen/dp/0321490452
running a risk because I put a book at the top slot I haven't read ;)
- http://ruby-doc.org/core-2.2.0/String.html
- http://ruby-doc.org/core-2.2.0/Array.html
- http://ruby-doc.org/core-2.2.0/Hash.html
- http://ruby-doc.org/core-2.2.0/Enumerable.html
Free online, considered the de factor tutorial: https://www.railstutorial.org/book
These are the rails guides are good highlevel: http://guides.rubyonrails.org/
The left column Models/Vides/Controllers are definitely the fundamentals.
- This screencast series is pretty modern but I haven't watched as much: https://www.rubytapas.com/
- Classic Destroy All Software, advanced but cool. Both Ruby and Rails. https://www.destroyallsoftware.com/screencasts/catalog
These repos are nice starts:
- micromachine - Minimal Finite State Machine https://github.com/soveran/micromachine
- scrivener - Validation frontend for models https://github.com/soveran/scrivener
- ohm - Object-Hash Mapping for Redis https://github.com/soveran/ohm
- cuba - Rum based microframework for web development https://github.com/soveran/cuba
- This is probably the most popular ruby framework outside Rails: http://www.sinatrarb.com/