Yeah, that post was for Robin's self-published book. This link is a paid interactive course based on the same material.
(FWIW, Max Stoiber did the same thing with his React/Redux/Immutable tutorial [0], and I'm actually hoping to turn my own "Practical Redux" tutorial series [1] into an Educative.io course in the near future as well.)
Thanks, glad you like it! I've paused the series for a bit so I can focus on some other tasks for the immediate near future, but have a bunch more topics that I plan to write about. If you're interested, I've got a list of tentatively planned blog posts at https://gist.github.com/markerikson/840fc9baf9598971ae252b92... .
https://news.ycombinator.com/item?id=13170837
Lots of upvotes, some discussion there.