skip_before_filter登录跳过验证必备

http://guides.rubyonrails.org/v3.0.8/action_controller_overview.html#filters  (例子来源)

http://apidock.com/rails/v3.0.5/AbstractController/Callbacks/ClassMethods/skip_filter

http://apidock.com/rails/ActionController/Filters/ClassMethods/skip_before_filter

登录前需要避开一些验证, 看官方文档给出的例子

class LoginsController < ApplicationController
  skip_before_filter :require_login, :only => [:new, :create]
end