The blog post explains gits feature of git commit --fixup and how it interacts with autosquashing during rebase. It suggests to enable autosquashing in the gitconfig and offers a nice alias for git fixup to make the selection of the fixup commit simpler.

[alias]
  fixup = "!git log -n 50 --pretty=format:'%h %s' --no-merges | fzf | cut -c -7 | xargs -o git commit --fixup"

[rebase]
  autosquash = true