backup.rb

# To install this script as a context menu item, add this to the registry:
#  key: \HKEY_CLASSES_ROOT\*\shell\Backup\command
#  default data: C:\Ruby26-x64\bin\rubyw.exe C:\Scripts\backup.rb "%1"
# And place this file at C:\Scripts\backup.rb

require 'fileutils'
require 'time'

src = ARGV.first
exit unless src

src_extension = File.extname(src)
src_basename = File.basename(src, src_extension)
time = Time.now.utc.iso8601
dest = "#{src_basename}_#{time}#{src_extension}"

FileUtils.cp(src, dest)