Uniq user name as clean non ascii characters

example.rb

first_and_last_name = "#{first_name}#{last_name}".downcase
first_and_last_name.gsub!("ğ", "g")
first_and_last_name.gsub!("ı", "i")
first_and_last_name.gsub!("ş", "s")
first_and_last_name.gsub!("ü", "u")
first_and_last_name.gsub!("ö", "o")
first_and_last_name.gsub!("ç", "c")
first_and_last_name.gsub!(/[^0-9A-Za-z]/, '')
index = 0
unique_user_name = loop do
  break first_and_last_name unless User.exists?(username: first_and_last_name)

  index += 1
  first_and_last_name = "#{first_and_last_name}#{index}"
end

self.username = unique_user_name