While there were quite a few seminal posts that impacted me strongly when I started out, for real, in Rails in 2012 (spent the 12 years prior coding in ColdFusion and Java), it was this one, far more recent, that really changed things for me/us at work:
I constantly refer to: https://www.speedshop.co/2019/01/10/three-activerecord-mistakes.html
While there were quite a few seminal posts that impacted me strongly when I started out, for real, in Rails in 2012 (spent the 12 years prior coding in ColdFusion and Java), it was this one, far more recent, that really changed things for me/us at work:
https://world.hey.com/dhh/stimulus-3-turbo-7-hotwire-1-0-9d507133
For me, the advent of the "Hotwire stack" has been, simply, huge.
My mind was blown when I read https://brunosutic.com/blog/async-ruby!
In my opinion, this "transparently concurrent" approach is a wonderful solution for doing async in Ruby.
Akshay Khot’s blog is bussin
https://www.akshaykhot.com/
Also anything from Honeybadger blog.
https://yehudakatz.com/2009/11/15/metaprogramming-in-ruby-its-all-about-the-self/
As Andy already recommended the one I was thinking, I'll recommend this https://www.schneems.com/2019/11/07/why-does-my-apps-memory-usage-grow-asymptotically-over-time/
This article opened my mind about some low level Ruby aspects. https://samsaffron.com/archive/2018/02/16/reducing-string-duplication-in-ruby
Here were a few thoughbot posts that had a big influence on me:
https://thoughtbot.com/blog/sandi-metz-rules-for-developers
https://thoughtbot.com/blog/tell-dont-ask
https://thoughtbot.com/blog/four-phase-test
This post about dependency injection in Ruby is neat: https://remimercier.com/dependency-injection-in-ruby/