解答例

.gitignore

@@ -29,3 +29,8 @@
 
 # Ignore master key for decrypting credentials and more.
 /config/master.key
+
+# Ignore vendor
+/vendor
+/vender
+

.node-version

@@ -0,0 +1 @@
+15.14.0

.rubocop.yml

@@ -1,4 +1,7 @@
 # This file overrides https://github.com/bbatsov/rubocop/blob/master/config/default.yml
+
+require:
+  - rubocop-rails
 
 AllCops:
   NewCops: enable

Gemfile

@@ -18,8 +18,6 @@ gem 'uglifier', '>= 1.3.0'
 
 # Use CoffeeScript for .coffee assets and views
 gem 'coffee-rails', '~> 4.2'
-# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
-gem 'turbolinks', '~> 5'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
 # gem 'jbuilder', '~> 2.5'
 # Use Redis adapter to run Action Cable in production
@@ -38,6 +36,7 @@ gem 'bootsnap', '>= 1.1.0', require: false
 
 gem 'bootstrap', '~> 4.5.0'
 gem 'font-awesome-sass', '~> 5.11.2'
+gem 'sassc', '2.1.0'
 gem 'jquery-rails'
 gem 'sorcery', '0.15.0'
 

Gemfile.lock

@@ -66,7 +66,7 @@ GEM
       rack-test (>= 0.6.3)
       regexp_parser (>= 1.5, < 3.0)
       xpath (~> 3.2)
-    childprocess (3.0.0)
+    childprocess (4.1.0)
     coderay (1.1.3)
     coffee-rails (4.2.2)
       coffee-script (>= 2.2.0)
@@ -96,7 +96,7 @@ GEM
     faraday-excon (1.1.0)
     faraday-net_http (1.0.1)
     faraday-net_http_persistent (1.1.0)
-    ffi (1.15.0)
+    ffi (1.15.5)
     font-awesome-sass (5.11.2)
       sassc (>= 1.11)
     globalid (0.4.2)
@@ -120,15 +120,15 @@ GEM
     marcel (1.0.1)
     method_source (1.0.0)
     mini_mime (1.1.0)
-    mini_portile2 (2.5.0)
+    mini_portile2 (2.8.4)
     minitest (5.14.4)
     msgpack (1.4.2)
     multi_json (1.15.0)
     multi_xml (0.6.0)
     multipart-post (2.1.1)
     nio4r (2.5.7)
-    nokogiri (1.11.3)
-      mini_portile2 (~> 2.5.0)
+    nokogiri (1.13.10)
+      mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
     oauth (0.5.6)
     oauth2 (1.4.7)
@@ -154,7 +154,7 @@ GEM
       pry (>= 0.10.4)
     public_suffix (4.0.6)
     puma (3.12.6)
-    racc (1.5.2)
+    racc (1.7.1)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -228,7 +228,7 @@ GEM
     ruby-progressbar (1.11.0)
     ruby2_keywords (0.0.4)
     ruby_dep (1.5.0)
-    rubyzip (2.3.0)
+    rubyzip (2.3.2)
     sass (3.7.4)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
@@ -240,16 +240,17 @@ GEM
       sprockets (>= 2.8, < 4.0)
       sprockets-rails (>= 2.0, < 4.0)
       tilt (>= 1.1, < 3)
-    sassc (2.4.0)
+    sassc (2.1.0)
       ffi (~> 1.9)
     sassc-rails (2.1.2)
       railties (>= 4.0.0)
       sassc (>= 2.0)
       sprockets (> 3.0)
       sprockets-rails
       tilt
-    selenium-webdriver (3.142.7)
-      childprocess (>= 0.5, < 4.0)
+    selenium-webdriver (4.1.0)
+      childprocess (>= 0.5, < 5.0)
+      rexml (~> 3.2, >= 3.2.5)
       rubyzip (>= 1.2.2)
     sorcery (0.15.0)
       bcrypt (~> 3.1)
@@ -270,9 +271,6 @@ GEM
     thor (1.1.0)
     thread_safe (0.3.6)
     tilt (2.0.10)
-    turbolinks (5.2.1)
-      turbolinks-source (~> 5.2)
-    turbolinks-source (5.2.0)
     tzinfo (1.2.9)
       thread_safe (~> 0.1)
     uglifier (4.2.0)
@@ -283,10 +281,10 @@ GEM
       activemodel (>= 5.0)
       bindex (>= 0.4.0)
       railties (>= 5.0)
-    webdrivers (4.6.0)
+    webdrivers (5.3.1)
       nokogiri (~> 1.6)
       rubyzip (>= 1.3.0)
-      selenium-webdriver (>= 3.0, < 4.0)
+      selenium-webdriver (~> 4.0, < 4.11)
     websocket-driver (0.7.3)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
@@ -320,11 +318,11 @@ DEPENDENCIES
   rubocop-checkstyle_formatter
   rubocop-rails
   sass-rails (~> 5.0)
+  sassc (= 2.1.0)
   sorcery (= 0.15.0)
   spring
   spring-watcher-listen (~> 2.0.0)
   sqlite3
-  turbolinks (~> 5)
   tzinfo-data
   uglifier (>= 1.3.0)
   web-console (>= 3.3.0)
@@ -334,4 +332,4 @@ RUBY VERSION
    ruby 2.6.6p146
 
 BUNDLED WITH
-   2.1.4
+   2.4.10

README.md

@@ -6,4 +6,7 @@
 
 - Ruby 2.6.6 を設定
 - プロジェクトで利用するgemをインストール
+  - `bundle config --local path 'vendor/bundle'` 
+  - `bundle config --local build.sassc -- --disable-march-tune-native`
+  - `bundle install`
 - データベース、テーブルを作成

app/assets/javascripts/application.js

@@ -15,5 +15,4 @@
 //= require bootstrap-sprockets
 //= require rails-ujs
 //= require activestorage
-//= require turbolinks
 //= require_tree .

app/controllers/application_controller.rb

@@ -1,2 +1,10 @@
 class ApplicationController < ActionController::Base
+  add_flash_types :success, :info, :warning, :danger
+  before_action :require_login
+
+  private
+
+  def not_authenticated
+    redirect_to login_path, warning: 'Please login first.'
+  end
 end

app/controllers/posts_controller.rb

@@ -19,10 +19,10 @@ def edit; end
 
   # POST /posts
   def create
-    @post = Post.new(post_params)
+    @post = current_user.posts.build(post_params)
 
     if @post.save
-      redirect_to @post, notice: 'Post was successfully created.'
+      redirect_to @post, success: 'Post was successfully created.'
     else
       render :new
     end
@@ -31,7 +31,7 @@ def create
   # PATCH/PUT /posts/1
   def update
     if @post.update(post_params)
-      redirect_to @post, notice: 'Post was successfully updated.'
+      redirect_to @post, success: 'Post was successfully updated.'
     else
       render :edit
     end
@@ -40,7 +40,7 @@ def update
   # DELETE /posts/1
   def destroy
     @post.destroy
-    redirect_to posts_url, notice: 'Post was successfully destroyed.'
+    redirect_to posts_url, success: 'Post was successfully destroyed.'
   end
 
   private

app/controllers/user_sessions_controller.rb

@@ -0,0 +1,20 @@
+class UserSessionsController < ApplicationController
+  skip_before_action :require_login, only: %i[new create]
+
+  def new; end
+
+  def create
+    @user = login(params[:email], params[:password])
+    if @user
+      redirect_back_or_to posts_path, success: 'Login successful.'
+    else
+      flash.now[:danger] = 'Login failed.'
+      render :new
+    end
+  end
+
+  def destroy
+    logout
+    redirect_to login_path, success: 'Logout successful.'
+  end
+end

app/controllers/users_controller.rb

@@ -0,0 +1,23 @@
+class UsersController < ApplicationController
+  skip_before_action :require_login, only: %i[new create]
+
+  def new
+    @user = User.new
+  end
+
+  def create
+    @user = User.new(user_params)
+    if @user.save
+      redirect_to login_path, success: 'User was successfully created.'
+    else
+      flash.now[:danger] = 'User creation failed.'
+      render :new
+    end
+  end
+
+  private
+
+  def user_params
+    params.require(:user).permit(:email, :password, :password_confirmation, :last_name, :first_name)
+  end
+end

app/models/post.rb

@@ -1,2 +1,6 @@
 class Post < ApplicationRecord
+  belongs_to :user
+
+  validates :title, presence: true, length: { maximum: 255 }
+  validates :content, presence: true, length: { maximum: 65_535 }
 end

app/models/user.rb

@@ -0,0 +1,20 @@
+class User < ApplicationRecord
+  authenticates_with_sorcery!
+
+  has_many :posts, dependent: :destroy
+
+  validates :password, length: { minimum: 3 }, if: -> { new_record? || changes[:crypted_password] }
+  validates :password, confirmation: true, if: -> { new_record? || changes[:crypted_password] }
+  validates :password_confirmation, presence: true, if: -> { new_record? || changes[:crypted_password] }
+
+  validates :email, uniqueness: true
+  validates :email, presence: true
+  validates :first_name, presence: true, length: { maximum: 255 }
+  validates :last_name, presence: true, length: { maximum: 255 }
+
+  def mine?(object)
+    # 呼び出し元のオブジェクトのIDを示す self.id を省略した記法。
+    # @user.mine?(object)のように利用すると、object.user_id と @user.id を比較する。
+    object.user_id == id
+  end
+end

app/views/layouts/application.html.erb

@@ -5,13 +5,16 @@
     <%= csrf_meta_tags %>
     <%= csp_meta_tag %>
 
-    <%= stylesheet_link_tag    'application', media: 'all', 'data-turbolinks-track': 'reload' %>
-    <%= javascript_include_tag 'application', 'data-turbolinks-track': 'reload' %>
+    <%= stylesheet_link_tag    'application', media: 'all' %>
+    <%= javascript_include_tag 'application' %>
   </head>
 
   <body>
-    <%= render 'shared/header' %>
-    <%# render 'shared/before_login_header' %>
+    <% if logged_in? %>
+      <%= render 'shared/header' %>
+    <% else %>
+      <%= render 'shared/before_login_header' %>
+    <% end %>
     <%= render 'shared/flash_message' %>
     <%= yield %>
     <%= render 'shared/footer' %>

app/views/posts/index.html.erb

@@ -15,8 +15,10 @@
         <td><%= post.title %></td>
         <td><%= post.content %></td>
         <td><%= link_to 'Show', post %></td>
-        <td><%= link_to 'Edit', edit_post_path(post) %></td>
-        <td><%= link_to 'Destroy', post, method: :delete, data: { confirm: 'Are you sure?' } %></td>
+        <% if current_user.mine?(post) %>
+          <td><%= link_to 'Edit', edit_post_path(post) %></td>
+          <td><%= link_to 'Destroy', post, method: :delete, data: { confirm: 'Are you sure?' } %></td>
+        <% end %>
       </tr>
     <% end %>
   </tbody>

app/views/posts/show.html.erb

@@ -7,6 +7,7 @@
   <strong>Content:</strong>
   <%= @post.content %>
 </p>
-
-<%= link_to 'Edit', edit_post_path(@post) %> |
+<% if current_user.mine?(@post) %>
+  <%= link_to 'Edit', edit_post_path(@post) %> |
+<% end %>
 <%= link_to 'Back', posts_path %>

app/views/shared/_before_login_header.html.erb

@@ -8,7 +8,7 @@
     <div class="collapse navbar-collapse" id="navbarSupportedContent">
       <ul class="navbar-nav ml-auto main-nav align-items-center">
         <li class="nav-item">
-          <%= link_to 'ログイン', login_path, class: 'nav-link' %>
+          <%= link_to 'Login', login_path, class: 'nav-link' %>
         </li>
       </ul>
     </div>

app/views/shared/_header.html.erb

@@ -13,24 +13,24 @@
           </a>
 
           <div class="dropdown-menu dropdown-menu-right">
-            <%= link_to 'Post一覧', posts_path, class: 'dropdown-item' %>
-            <%= link_to 'Post作成', new_post_path, class: 'dropdown-item' %>
+            <%= link_to 'List of Posts', posts_path, class: 'dropdown-item' %>
+            <%= link_to 'New Post', new_post_path, class: 'dropdown-item' %>
           </div>
         </li>
 
         <li class="nav-item">
-          <%= link_to 'Like一覧', '#', class: 'nav-link' %>
+          <%= link_to 'List of Likes', '#', class: 'nav-link' %>
         </li>
 
         <li class="nav-item dropdown dropdown-slide">
           <a href="#" class="nav-link" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" id="header-profile">
             <%= image_tag 'sample', size: '40x40', class: 'rounded-circle mr15'%>
           </a>
           <div class="dropdown-menu dropdown-menu-right">
-            <div class="dropdown-item"><%# "#{current_user.last_name} #{current_user.first_name}" %></div>
+            <div class="dropdown-item"><%= "#{current_user.last_name} #{current_user.first_name}" %></div>
             <div class="dropdown-divider"></div>
-            <%= link_to 'プロフィール', '#', class: 'dropdown-item' %>
-            <%= link_to 'ログアウト', '#', class: 'dropdown-item' %>
+            <%= link_to 'Profile', '#', class: 'dropdown-item' %>
+            <%= link_to 'Logout', logout_path, method: :delete, class: 'dropdown-item' %>
           </div>
         </li>
       </ul>

app/views/user_sessions/new.html.erb

@@ -0,0 +1,25 @@
+<div class="container">
+  <div class="row">
+    <div class=" col-md-10 offset-md-1 col-lg-8 offset-lg-2">
+      <h1>Login</h1>
+      <%= form_with url: login_path, local: true do |f| %>
+        <div class="form-group">
+          <%= f.label :email %>
+          <%= f.email_field :email, class: 'form-control' %>
+        </div>
+        <div class="form-group">
+          <%= f.label :password %>
+          <%= f.password_field :password, class: 'form-control' %>
+        </div>
+        <div class="actions">
+          <%= f.submit 'Login', class: 'btn btn-primary' %>
+        </div>
+      <% end %>
+      <div class='text-center'>
+        <%= link_to 'Signup', new_user_path %>
+        <a href="#">Forget Password?</a>
+      </div>
+    </div>
+  </div>
+</div>
+