module Api
  class ArticlesController < ApplicationController

    def index
      articles = Article.select(:id, :title, :content, :created_at).order('created_at desc').page(params[:page] || 1).per(Article.count)
      count = articles.count rescue 0

      render json: {articles: articles, count: count}
    end

    def show
      article = Article.find(params[:id])
      render json: article
    end
  end
 end

Rails.application.routes.draw do
   namespace :api do
    resources :articles, only: [:index, :show]
  end
end

bundle exec rails server