[dmix]

At a minimum it's useful having the `.tool-versions` dotfile in a project directory which lists the versions of each language, db, and package manager version (our Rails project lists versions for ruby, bundler, postgres, node, yarn, redis). Even if all devs don't use asdf, it's a useful reference point.

https://asdf-vm.com/manage/configuration.html#tool-versions

Similar to an `.editorconfig` to globally define stuff like tab widths for IDEs.