[2017][ruby][7.x] move back to ARGF

2017/ruby/day_07.rb

@@ -1,7 +1,7 @@
 Program = Struct.new(:name, :weight, :disc)
 
 programs = {}
-File.read(File.expand_path("../input/day_07.txt")).strip.split("\n").each do |line|
+ARGF.read.strip.split("\n").each do |line|
   name, weight, above = line.scan(/(.+) \((\d+)\)(?: -> (.+))?/)[0]
   programs[name] = Program.new(name, weight.to_i, (above || "").split(", "))
 end