# File lib/capistrano/configuration/roles.rb, line 45
      def role(which, *args, &block)
        options = args.last.is_a?(Hash) ? args.pop : {}
        which = which.to_sym
        roles[which].push(block, options) if block_given?
        args.each { |host| roles[which] << ServerDefinition.new(host, options) }
      end