We were using Capistrano's shared folder because it was the default
folder used by the capistrano-puma gem. However, it's easier to manage
it if it's under version control.
So we're moving the old `puma.rb` to `puma/development.rb`, and we use
the new `puma.rb` file for all environments except development. Anyone
installing CONSUL can change these files at will or change the specific
files for preproduction, production and staging environments.
