class Registry::Git

def checkout
  if project_in_git?
    system "git submodule add #{url} vendor/extensions/#{name}"
    cd(File.join('vendor', 'extensions', name)) do
      system "git submodule init && git submodule update"
    end
  else
    super
    cd(path) do
      system "git submodule init && git submodule update"
    end
  end
end