This is the revamped edition of ruby Racer.

racer_utils.rb

class Die
  def initialize(sides = 6)
    @sides = sides
  end
  
  # Remember: rand(N) randomly returns one of N consecutive integers, starting at 0
  # So rand(N) returns a random integer in (0..N-1)
  # And 1 + rand(N) returns a random integer in (1..N)
  # See: http://www.ruby-doc.org/core-1.9.3/Kernel.html#method-i-rand
  def roll
    1 + rand(@sides)
  end
end
 
# Use "reputs" to print over a previously printed line,
# assuming the cursor is positioned appropriately.
def reputs(str = '')
  puts "\e[0K" + str
end
 
# Clear the screen
def clear_screen!
  print "\e[2J"
end
 
# Moves cursor to the top left of the terminal
def move_to_home!
  print "\e[H"
end
 
# Flushes the STDOUT buffer.
# By default STDOUT is only flushed when it encounters a newline (\n) character
def flush!
  $stdout.flush
end

rub_racer_2.rb

require_relative 'racer_utils'
 
class RubyRacer
  attr_reader :players, :length
 
  def initialize(players, length = 30)
    @players = players
    @length = length
    @player_position = Hash[players.map{|player| [player,0]}]
    @board = Hash.new
    @dice = Die.new
    @winner = nil  
  end
  
  # Returns +true+ if one of the players has reached 
  # the finish line, +false+ otherwise
  def finished?
    @finished
  end
  
  # Returns the winner if there is one, +nil+ otherwise
  def winner(player = @player)
    if @player_position[player] == @length - 1
    @finished = true
	  @winner = player
	else
	  @winner
	end
  end
  
  # Rolls the dice and advances +player+ accordingly
  def advance_player!(player)
    @player_position[player] += @dice.roll
    
    if @player_position[player] > @length - 1
      @player_position[player] = @length -1
      clear_screen!
      print_board
    end
    winner(player)
  end
  # Prints the current game board
  # The board should have the same dimensions each time
  # and you should use the "reputs" helper to print over
  # the previous board
  def print_board
    @players.each do |player|
      print " |" * @player_position[player]
      reputs(player + "|" + " |" * (@length - @player_position[player] - 1))
    end
  end
end
 
players = ['a', 'b']
 
game = RubyRacer.new(players)
 
# This clears the screen, so the fun can begin
clear_screen!
 
until game.finished?
  players.each do |player|
   players.each do |player|
    @player = player
    move_to_home!
    game.print_board
    game.advance_player!(@player)
    sleep(0.2)
  end
end
end
 
# The game is over, so we need to print the "winning" board
 
puts "Player '#{game.winner}' has won!"