class IsCuracaoPhoneValidator

(It’s probably a fake regex but hey, it looks legit.)
taken from lindsaar.net/2010/1/31/validates_rails_3_awesome_is_true<br>validates :email, :presence => true, :is_email_address => true;
in your model, add:
== usage:
-*- encoding : utf-8 -*-

def error_message 

def error_message
  "is geen geldig Curaçao telefoon nummer."
end

def help_message 

def help_message
  "Telefoonnummer moet 7 cijfers zijn, bijvoorbeeld 6781256."
end

def validate_each(record, attribute, value) 

def validate_each(record, attribute, value)
  unless value =~ /[4-8][0-9]{6}/
    record.errors[attribute] << (options[:message] || error_message )
  end
end