安装 homebrew
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew search 
brew install nginx
install rails under vpn
http://blog.csdn.net/xunyn/article/details/17069521
https://ruby-china.org/wiki/install_ruby_guide
http://stackoverflow.com/questions/15514865/brew-update-errors
install rvm 
https://ruby-china.org/wiki/install_ruby_guide
install ruby under vpn
if ruby -v == 2.1.1 
  rvm system --default
else 
  rvm install 2.1.1   #under vpn
  rvm 2.1.1 --default
bundle install # install all in gemfile
if error
  brew install mysql
  mysqld
cp database.yml.example database.yml
vim config/database.yml
rake db:create:all
rake db:migrate
rails s
rake -T| grep seed
执行所有seek命令.
rake assets:precompile RAILS_ENV=production
如果使用 system ruby 则 gem安装于 ~/.gem文件夹下面
如果使用 rvm安装ruby 则 gem安装于 ~/.rvm/.gem下面
rails也是一个gem
1. rails s 命令行可以展示每个请求的请求模块和profile信息.
请求主页. 首先访问: routes.rb
  root ‘home#index‘
  resources :roles
路由至: home_controller.rb
  skip_before_filter :authenticate_user! 	// 跳过用户认证
  skip_authorization_check					// 跳过用户认证
  before_action :redirect_to_login_if_in_subdomain 	// 如果是二级域名, 跳转到登陆界面
  def index
  end
index函数为空, 直接查找 views/layouts/home.html.erb -> views/home
不同action 根据action 来做一些样式的改变.
http://localhost:3000/login
请求登陆界面: routes.rb
get "/login" => "sessions#new"
devise.sessions_controller
	
  prepend_before_filter :require_no_authentication, only: [ :new, :create ]
  prepend_before_filter :allow_params_authentication!, only: :create
  prepend_before_filter only: [ :create, :destroy ] { request.env["devise.skip_timeout"] = true }
  # GET /resource/sign_in
  def new
    self.resource = resource_class.new(sign_in_params)
    clean_up_passwords(resource)
    respond_with(resource, serialize_options(resource))
  end
原文:http://www.cnblogs.com/codesay/p/4345404.html