app/validators/ccd_email_validator.rb
class CcdEmailValidator < ActiveModel::EachValidator
REGEX = /^([a-zA-Z0-9_\-.]+)@([a-zA-Z0-9_\-.]+)\.([a-zA-Z]{2,5})$/
def validate_each(record, attribute, value)
record.errors.add(attribute, :invalid_ccd_email) unless value.nil? || value =~ REGEX
end
end