Ruby on rails 创建后，设置角色

我正在尝试使用after_create将默认用户角色设置为subscriber。但它似乎没有做出任何改变。新用户的角色始终为[“”]

用户模型

class User < ActiveRecord::Base

  acts_as_authentic
  after_create :set_sub
  after_create :set_universal
  after_create :set_carrier

  def set_sub
    self.roles << "subscriber"
    #self.roles_mask = 4
  end

  def set_universal
      self.channels << Channel.find(1)
  end

  def set_carrier
    @carrier = Carrier.with_name(self.carrier_name)
    self.carrier<< @carrier
  end

  ROLES = %w[admin  moderator subscriber]

  #Each user can subscribe to many channels
  has_and_belongs_to_many :channels

  #Each user who is a moderator can moderate many channels
  #has_many :channel_mods
  has_and_belongs_to_many :modifies , :class_name => "Channel"

  #Each user can receive many messages
  has_and_belongs_to_many :messages

  #Each user belongs to a carrier
  belongs_to :carrier

  #Filter users by role(s)
  named_scope :with_role, lambda { |role| {:conditions => "roles_mask & #{2**ROLES.index(role.to_s)} > 0 "} }

  def roles  
    ROLES.reject { |r| ((roles_mask || 0) & 2**ROLES.index(r)).zero? }  
  end

  def roles=(roles)  
    self.roles_mask = (roles & ROLES).map { |r| 2**ROLES.index(r) }.sum  
  end

  def role_symbols
  roles.map do |role|
    role.underscore.to_sym  # NOT role.name.underscore.to_sym (role is a string)
    end
  end


end

class用户self.roles在方法集中，您可以执行self.roles

def set_sub
  self.roles = [ "subscriber" ]
end