```ruby
class ArticlesController < ApplicationController
  before_action :authenticate_user!, except: [:index, :show]
  before_action :set_article, only: [:show, :edit, :update, :destroy]

  # GET /articles
  def index
    @articles = Article.all.includes(:user)
  end

  # GET /articles/1
  def show
    @comment = Comment.new
  end

  # GET /articles/new
  def new
    @article = Article.new
  end

  # GET /articles/1/edit
  def edit
  end

  # POST /articles
  def create
    @article = Article.new(article_params)
    @article.user = current_user

    if @article.save
      @article.notify :users
      redirect_to @article, notice: 'Article was successfully created.'
    else
      render :new
    end
  end

  # PATCH/PUT /articles/1
  def update
    if @article.update(article_params)
      redirect_to @article, notice: 'Article was successfully updated.'
    else
      render :edit
    end
  end

  # DELETE /articles/1
  def destroy
    @article.destroy
    redirect_to articles_url, notice: 'Article was successfully destroyed.'
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_article
      @article = Article.includes(:user).find(id: params[:id])
    end

    # Only allow a trusted parameter "white list" through.
    def article_params
      params.require(:article).permit(:title, :body)
    end
end
```

Fix a bug of test apps
user
```ruby
class ArticlesController < ApplicationController
  before_action :authenticate_user!, except: [:index, :show]
  before_action :set_article, only: [:show, :edit, :update, :destroy]

  # GET /articles
  def index
    @articles = Article.all.includes(:user)
  end

  # GET /articles/1
  def show
    @comment = Comment.new
  end

  # GET /articles/new
  def new
    @article = Article.new
  end

  # GET /articles/1/edit
  def edit
  end

  # POST /articles
  def create
    @article = Article.new(article_params)
    @article.user = current_user

    if @article.save
      @article.notify :users
      redirect_to @article, notice: 'Article was successfully created.'
    else
      render :new
    end
  end

  # PATCH/PUT /articles/1
  def update
    if @article.update(article_params)
      redirect_to @article, notice: 'Article was successfully updated.'
    else
      render :edit
    end
  end

  # DELETE /articles/1
  def destroy
    @article.destroy
    redirect_to articles_url, notice: 'Article was successfully destroyed.'
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_article
      @article = Article.includes(:user).find(params[:id])
    end

    # Only allow a trusted parameter "white list" through.
    def article_params
      params.require(:article).permit(:title, :body)
    end
end
```
assistant