Update dependencies and improve local env setup #34
Description
Hello there!
Thanks for this repo and the associated book.
While going through the online version of the book, I tried to run this repository locally, but struggled overall. For example, it was difficult to get the older version of Elixir, I was not sure about the appropriate OTP version, etc. It was a bit tricky to set this up with all appropriate system/application dependencies and getting it to compile/run.
After a while, I did however get a minimal version of this running on my own fork/ branch here. I updated some dependencies (not all), made it compile and also made the tests pass.
I wonder if there's any interest in getting some/any of these changes into master here, via a PR ? (Link to diff.)