Pronto is an external tool which is use to check code conventions and is
not needed to run the application, just like rubocop or scss-lint.
Loading it caused a couple of issues. First, it loaded BetterHtml, and
we had to disable it in order to avoid crashes in the development
environment.
Second, it loaded ruby-progressbar, which loads the ProgressBar class,
which conflicts with our own ProgressBar class. This made the
application crash whenever the ProgressBar class was used.