Rails Devise集成 #

gem 'devise'

bundle install
rails generate devise:install
rails generate devise User
rails db:migrate

# config/routes.rb
Rails.application.routes.draw do
  devise_for :users
end

class User < ApplicationRecord
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :validatable
end

class ArticlesController < ApplicationController
  before_action :authenticate_user!
end

<% if user_signed_in? %>
  <%= current_user.email %>
  <%= button_to '退出', destroy_user_session_path, method: :delete %>
<% else %>
  <%= link_to '登录', new_user_session_path %>
<% end %>