def self.create_from_twitter(username, pass)
    user = new(
      :name => username,
      :password => pass
    )
    user.save(:validate => false) or raise "Couldn't create new user"

    external_user = Vodpod::ExternalUser.create(
        :user => user,
        :identifier => username,
        :service => 'twitter'
    ) or raise "Couldn't create external user"

    user
  end