Dirgutter provides signs for dirvish buffers just like gitgutter does for file buffers.
This plugin is in an early alpha stage!
I would recommend using minpac which makes extensive use of the package feature which was added to Vim 8 and Neovim.
call minpac#add('https://gitlab.com/mrossinek/vim-dirgutter')
Other package managers work in a similar fashion.
Dirgutter provides a single command: :Dirgutter which populates the
sign-column with the results of the short git status command.
It also sets up an autocommand to run this command whenever entering a buffer.
For more information take a look at :help dirgutter.