# encoding: utf-8
# String
class String
  # Underline a string
  #
  # @param [String] character ('-')
  #   The character used to underline the string
  #
  # @return [String]
  #   The string + underline
  def underline(character: '-')
    result = []
    result << self
    result << gsub(/./, character)

    result.join("\n")
  end
end