4-3加入admin复盘

1. git checkout -b story2
2. 在admin/controller加入
   before_action :authenticate_user!
   before_action :admin_required
   3.application_controller.rb
   加入：
   def admin_required
   if !current_user.admin?
   redirect_to "/", alert: "You are not admin."
   end
   end
   4.user.rb
   def admin?
   is_admin
   end
3. rails g migration add_is_admin_to_user
   加入：
   add_column :users, :is_admin, :boolean, default: false
   rake db:migrate

rails c
u = User.new(email: "admin@test.com", password: "123456", password_confirmation: "123456")
u.save
u.is_admin = true
u.save
7.seeds.rb
u = User.new
u.email = "admin@test.com"
u.password = "123456"
u.password_confirmation = "123456"
u.is_admin = true
u.save
8.layout
layout "admin"
touch app/views/layouts/admin.html.erb