the twotone.io site builds from published posts pushed by foresty.io CMS
Forestry.io no longer exists. Porting to Tina. Whilst still a jekyll site...
npx tinacms dev -c "jekyll serve"
Ruby might be broken... things to try
bundle update --bundler
eval "$(rbenv init -)"
source ~/.bash_profile
then try the command again
at this point admin will hopefully be
http://localhost:4000/admin/index.html
and site
http://127.0.0.1:4000
https://tina.io/docs/frameworks/jekyll/