Generates a cap2-like REVISION file when using cap3

git_revision_file.cap

require 'capistrano/git'
namespace :git do
  after :create_release, :write_revision do
    on roles :all do
      with fetch(:git_environmental_variables) do
        within repo_path do
          execute :git, :log, '-1', '--format=%H', '>', release_path.join('REVISION')
        end
      end
    end
  end
end