Add a runner for ruby

ruby/runner.rb

@@ -0,0 +1,32 @@
+#!/usr/bin/ruby -w
+
+require 'fileutils'
+
+require File.join(File.dirname(__FILE__), 'gilded_rose')
+
+if ARGV.length != 2
+  puts "Usage: ruby runner.rb <in-file> <out-file>"
+  exit 1
+end
+
+in_file, out_file = ARGV
+
+puts "Reading from #{in_file}, writing to #{out_file}"
+
+items = IO.readlines(in_file)
+  .map(&:strip)
+  .reject { |l| l.empty? || l.start_with?(";") }
+  .map { |l| l.split("__") }
+  .map { |name, sell_in, quality|
+    Item.new(name, sell_in.to_i, quality.to_i)
+  }
+
+rose = GildedRose.new(items)
+rose.update_quality
+
+output = items
+  .map { |i| [i.name, i.sell_in, i.quality].join("__") }
+  .join("\n")
+
+FileUtils.mkdir_p(File.dirname(out_file))
+IO.write(out_file, output)