simple token auth user model, this is an comment code from : https://gist.github.com/gonzalo-bulnes/9001010

gistfile1.rb

class User < ActiveRecord::Base
  before_save :ensure_authentication_token

  # Include default devise modules. Others available are:
  # :confirmable, :lockable, :timeoutable and :omniauthable
  devise :database_authenticatable, :registerable, :timeoutable,
         :recoverable, :rememberable, :trackable, :validatable, :lockable


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

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