First need install erlang-elixir-mix properly
Now you will need a global installation of mix credo and bunt.
To install blunt (globally)
git clone https://github.com/rrrene/bunt cd bunt mix archive.build mix archive.install
To install credo (globally):
git clone https://github.com/rrrene/credo cd credo mix archive.build mix archive.install
After install successfully credo globally you simple need install this gem
gem install pronto-credo
After the gem is installed, Pronto will already detect credo runner inside a elixir project.
You can configure what checkers need in the project using