refactor_test.rb

#Refactor following code using singleton pattern and explain your answer
require 'singleton'

class Logger

  include Singleton

  LOG_FILE_NAME = 'dev.log'

  def initialize 
    @file = File.exists?('dev.log') ? File.open('dev.log', 'a') : File.new('dev.log', 'a') 
  end 

  def <<(msg)
    @file << msg
  end

end

class SM1 

  def initialize 
    Logger.instance  << 'Just creating ' + self.class.to_s + "\n"            
  end 

end 

class SM2 

  def initialize 
    Logger.instance << 'Just creating ' + self.class.to_s + "\n"          
  end 

  def say_hi 
    puts 'Hi somebody' 
    Logger.instance << "Just said hi\n"             
  end 

end 

class SM3 

  def to_str 
    msg = "I'm a #{self.class.to_s} hell yeah" 
    Logger.instance << msg      
    msg 
  end 

end 


# Usage test
sm1 = SM1.new 
sm2 = SM2.new 
sm2.say_hi 
sm3 = SM3.new 
p sm3.to_str