Hi, 今天看到一段代码：

来源：https://www.digitalocean.com/community/tutorials/how-to-configure-devise-and-omniauth-for-your-rails-application

class User < ActiveRecord::Base
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable,
     :omniauthable, :omniauth_providers => [:digitalocean]

  def self.from_omniauth(auth)
      where(provider: auth.provider, uid: auth.uid).first_or_create do |user|
        user.provider = auth.provider
        user.uid = auth.uid
        user.email = auth.info.email
        user.password = Devise.friendly_token[0,20]
      end
  end
end

在 method from_omniauth 中，调用 where 时前面没有调用它的 object，正常写法应该是 User.where(...) 吧，这是 Rails 的一种默认方式吗？