Let's say I had the email address like putin-crab@?????????.??

How to validate that address in rails 3.1?

My Model(i use Mongoid):

#encoding: utf-8
class User
  include Mongoid::Document

  field :email,    :type => String
  validates :email,    :presence => true, :format => { :with => RFC822::EMAIL }
end

For validations reqexp i use gem https://github.com/dim/rfc-822

in rails console (normal email):

ruby-1.9.2-p290 :001 > usr = User.new( :email => "[email protected]" )
 => #<User _id: 4ec627cf4934db7e4d000001, _type: nil, email: "[email protected]"> 
ruby-1.9.2-p290 :002 > usr.valid?
 => true 

in rails console (fu@#ing email):

ruby-1.9.2-p290 :003 > usr = User.new( :email => "putin-crab@?????????.??" )
 => #<User _id: 4ec627f44934db7e4d000002, _type: nil, email: "putin-crab@?????????.??"> 
ruby-1.9.2-p290 :004 > usr.valid?

Encoding::CompatibilityError: incompatible encoding regexp match (ASCII-8BIT regexp with UTF-8 string)
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validations/format.rb:9:in `=~'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validations/format.rb:9:in `!~'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validations/format.rb:9:in `validate_each'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validator.rb:153:in `block in validate'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validator.rb:150:in `each'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validator.rb:150:in `validate'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activesupport-3.1.1/lib/active_support/callbacks.rb:302:in `_callback_before_13'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activesupport-3.1.1/lib/active_support/callbacks.rb:404:in `_run_validate_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activesupport-3.1.1/lib/active_support/callbacks.rb:81:in `run_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/callbacks.rb:42:in `block in run_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/callbacks.rb:67:in `call'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/callbacks.rb:67:in `run_cascading_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/callbacks.rb:41:in `run_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validations.rb:212:in `run_validations!'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validations/callbacks.rb:53:in `block in run_validations!'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activesupport-3.1.1/lib/active_support/callbacks.rb:390:in `_run_validation_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activesupport-3.1.1/lib/active_support/callbacks.rb:81:in `run_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/callbacks.rb:42:in `block in run_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/callbacks.rb:67:in `call'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/callbacks.rb:67:in `run_cascading_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/callbacks.rb:41:in `run_callbacks'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validations/callbacks.rb:53:in `run_validations!'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/activemodel-3.1.1/lib/active_model/validations.rb:179:in `valid?'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/mongoid-2.3.3/lib/mongoid/validations.rb:70:in `valid?'
    from (irb):4
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/railties-3.1.1/lib/rails/commands/console.rb:45:in `start'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/railties-3.1.1/lib/rails/commands/console.rb:8:in `start'
    from /home/username/.rvm/gems/ruby-1.9.2-p290@rail31/gems/railties-3.1.1/lib/rails/commands.rb:40:in `<top (required)>'
    from script/rails:6:in `require'