Allowing both comma or dot in currency parameter

I have this in my model:

  monetize :advance_amount_cents, allow_nil: true
  monetize :rental_amount_cents, allow_nil: true

I use AutoNumeric to display the currency. It sends it back to the controller like this in params:

'rental_amount' = "2050.12"

Which returns this error from the model:

activerecord.errors.models.rental_period.attributes.rental_amount.invalid_currency

It accepts the currency when I can get it to be sent with a comma instead of a dot as decimal. What is the best practise here? Ideally I would like for all attributes that are monetized to accept anything as decimal separator, comma or dot. That's also how Monetize seems to do it:

pry(main)> Monetize.parse "2050.12"
=> #<Money fractional:205012 currency:USD>
pry(main)> Monetize.parse "2050,12"
=> #<Money fractional:205012 currency:USD>

Which is perfect. How can I configure my model (or the Monetize gem in general) to accept both as params (dot or comma).

Solution

Hopefully this is of use to someone.

Model:

monetize :rental_amount_cents, allow_nil: true

View:

  = f.input :rental_amount, label: 'Rental amount' do
    .input-group
      = text_field_tag :rental_amount, @rental_period.rental_amount, class: 'form-control', id: "#{@rental_period.new_record? ? '' : (@rental_period.id.to_s + '_')}rental_amount_rate_rendered"
      = f.hidden_field :rental_amount, class: 'rate-input'
      %span.input-group-addon €

Javascript setup:

$('[id$=rate_rendered]').add('.flex-rate').autoNumeric('init', settings.money_nosign).on('keyup', function() {
  var $hid;
  $hid = $(this).parent().find('input.rate-input');
  if ($(this).autoNumeric('get') !== '') {
    return $hid.val($(this).autoNumeric('get').replace('.', ','));
  } else {
    return $hid.val(0);
  }
});

In settings I have (only relevant part:

window.settings = {
  money_nosign: {
    aDec: ',',
    aSep: '.',
    vMin: '-999999999.99'
  }
};