Remove vietnamese accent ruby

slug.ruby

from = "àáãảạăằắẳẵặâầấẩẫậèéẻẽẹêềếểễệđùúủũụưừứửữựòóỏõọôồốổỗộơờớởỡợìíỉĩịýỷỳỹỵäëïîöüûñç·/_,:;"
to   = "aaaaaaaaaaaaaaaaaeeeeeeeeeeeduuuuuuuuuuuoooooooooooooooooiiiiiyyyyyaeiiouunc------"

str = "DEMO STRING"

hash = {}
for i in 0..from.length - 1
  hash[from[i]] = to[i]
end

str.downcase.gsub(/[àáãảạăằắẳẵặâầấẩẫậèéẻẽẹêềếểễệđùúủũụưừứửữựòóỏõọôồốổỗộơờớởỡợìíỉĩịýỷỳỹỵäëïîöüûñç·/_,:;]/, hash)
str = str.gsub(/[^a-z0-9 -]/, '') # remove invalid chars
        .gsub(/\s+/, '-') # remove white space
        .gsub(/-+/, '-')


# inspired by:
https://gist.github.com/bluzky/b8c205c98ff3318907b30c3e0da4bf3f