ruby colorize string

color_string.rb

class String
  def black;  "\e[30m#{self}\e[0m" end 
  def red;    "\e[31m#{self}\e[0m" end 
  def green;  "\e[32m#{self}\e[0m" end 
  def brown;  "\e[33m#{self}\e[0m" end 
  def blue;   "\e[34m#{self}\e[0m" end 
  def magenta;"\e[35m#{self}\e[0m" end 
  def cyan;   "\e[36m#{self}\e[0m" end 
  def gray;   "\e[37m#{self}\e[0m" end
end

puts "My color is green".green 
puts "My color is blue.".blue