Ruby script to sanitize Vietnamese "marks"

vietnamese_sanitizer.rb

dic = {
  'áàảãạăắặằẳẵâấầẩẫậ': 'a',
  'ÁÀẢÃẠĂẮẶẰẲẴÂẤẦẨẪẬ': 'A',
  'đ': 'd',
  'Đ': 'D',
  'éèẻẽẹêếềểễệ': 'e',
  'ÉÈẺẼẸÊẾỀỂỄỆ': 'E',
  'íìỉĩị': 'i',
  'ÍÌỈĨỊ': 'I',
  'óòỏõọôốồổỗộơớờởỡợ': 'o',
  'ÓÒỎÕỌÔỐỒỔỖỘƠỚỜỞỠỢ': 'O',
  'úùủũụưứừửữự': 'u',
  'ÚÙỦŨỤƯỨỪỬỮỰ': 'U',
  'ýỳỷỹỵ': 'y',
  'ÝỲỶỸỴ': 'Y'
}

from_string = dic.keys.join
# => áàảãạăắặằẳẵâấầẩẫậÁÀẢÃẠĂẮẶẰẲẴÂẤẦẨẪẬđĐ...ýỳỷỹỵÝỲỶỸỴ

to_string = ''
dic.each { |key, value| to_string << (value * key.length) } 
# => aaaaaaaaaaaaaaaaaAAAAAAAAAAAAAAAAAdD...yyyyyYYYYY

str = 'Xin chào, Tôi là Phan Thái Phong'
str.tr(from_string, to_string) # Xin chao, Toi la Phan Thai Phong