brazilian currency formating (Ruby on Rails - attributes api)

br_money_type.rb

# app/types/br_money_type.rb
class BrMoneyType < ActiveRecord::Type::Decimal
  def cast(value)
    value.is_a?(String) ? value.clean_money : value
  end

  def deserialize(value)
    value ? value.to_f : value
  end
end

model.rb

# model.rb
attribute :value, :br_money
attribute :discount_value, :br_money

# console
# Model.create(value: '1.850,25', discount_value: 'R$ 5.300,89')
# Model.last.value => 1850.25
# Model.last.discount_value => 5300.89

string_ex.rb

# config/initializers/string_ext.rb
class String
  # Convert a money string ('R$ 10.000,00') to float (10000.0)
  def clean_money
    self.gsub(/[^\d,]/, '').gsub(',', '.').strip.to_f
  end
end

types.rb

# config/initializers/types.rb
ActiveRecord::Type.register(:br_money, BrMoneyType)