ruby-on-rails-4 – Rails 4模型总是返回nil

我正在使用devise来管理身份验证.

这是db表：

CREATE TABLE users
(
  id serial NOT NULL,email character varying(255) NOT NULL DEFAULT ''::character varying,encrypted_password character varying(255) NOT NULL DEFAULT ''::character varying,reset_password_token character varying(255),reset_password_sent_at timestamp without time zone,remember_created_at timestamp without time zone,sign_in_count integer NOT NULL DEFAULT 0,current_sign_in_at timestamp without time zone,last_sign_in_at timestamp without time zone,current_sign_in_ip character varying(255),last_sign_in_ip character varying(255),name character varying(255),lastname character varying(255),birthday timestamp without time zone,gender character varying(255),created_at timestamp without time zone,updated_at timestamp without time zone,authentication_token character varying(255),facebook_uid character varying(255),gplus_uid character varying(255),CONSTRAINT users_pkey PRIMARY KEY (id)
)
WITH (
  OIDS=FALSE
);

这就是模型

#encoding: utf-8
class User < ActiveRecord::Base

  has_many :user_benefits
  has_many :benefits,through: :user_benefits

  devise :database_authenticatable,:registerable,:recoverable,:rememberable,:trackable,:validatable

  validates :gender,:inclusion => { :in => %w(m f)}
  validates :email,email_format: { message: "Email invalido" }

  before_save :ensure_authentication_token

  def ensure_authentication_token
    if authentication_token.blank?
      self.authentication_token = generate_authentication_token
    end
  end

  def set_gender new_gender

    case new_gender.downcase
      when "male"
        self.gender = 'm'
      when "female"
        self.gender = 'f'
      when "m"
        self.gender = 'm'
      when "f"
        self.gender = 'f'
      else
        self.gender = nil
    end

  end

  def get_response
    {
        :auth_token=>self.authentication_token,:user => {
          :email=> self.email,:name=> self.name,:lastname=> self.lastname,:birthday=> self.birthday,:gender=> self.gender,:auth_token=> self.authentication_token,:created_at=> self.created_at,:updated_at=> self.updated_at,:facebook_uid=> self.facebook_uid,:gplus_uid=> self.gplus_uid
        }
    }
  end

  private

  def generate_authentication_token
    loop do
      token = Devise.friendly_token
      break token unless User.where(authentication_token: token).first
    end
  end

end

当我打电话给get_response时,我得到了：

{
  auth_token: "fRoi1RPTuP64m55jXCSS"
  user: {
    email: "testg@habitues.com"
    name: "Lalo"
    lastname: "Landa"
    birthday: null
    gender: "m"
    auth_token: "fRoi1RPTuP64m55jXCSS"
    created_at: null
    updated_at: "2013-11-27T20:14:22.534-03:00"
    facebook_uid: null
    gplus_uid: null
  }
  new: false
}

有人有想法吗？

谢谢