def print
      value = [name]
      steps.each_with_index do |step, index|
        value << "#{(index + 1).to_s.rjust(3)}. #{step.first}"
      end
      puts value.join("\n")
    end
def print
      value = [name]
      steps.each_with_index do |step, index|
        value << "#{(index + 1).to_s.rjust(3)}. #{step.first}"
      end
      puts value.join("\n")
    end
Prints/puts a String representation of the formula.
 @example
   Hero::Formula[:example].add_step(:one) {}
   Hero::Formula[:example].add_step(:two) {}
   Hero::Formula[:example].add_step(:three) {}
   Hero::Formula[:example].to_s # => "example\n  1. one\n  2. two\n  3. three"