app/validators/email_validator.rb
##
# Email format validator
#
class EmailValidator < ActiveModel::EachValidator
##
# Validator
#
def validate_each(record, attribute, value)
record.errors[attribute] << ('The email is not valid') unless value =~ /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i
end
end