delete trailing white space

wanco.rb

Dir["app/**/*.rb"].each do |file|
  File.open(file, "rb+") do |io|
    result = []
    body = io.read
    body.split("\n").each do |line|
      line.gsub!(/\s+\z/, "")
      result << line
      puts line
    end
    io.rewind
    io.write result.join("\n")
  end
end