问Rails 4.2:无法添加搜索功能。

EN

<p>This is the articles placeholder</p>

<%= form_tag articles_path, :method => 'get' do %>
    <%= text_field_tag :search, params[:search] %>
    <%= submit_tag "Search" %>

<% end %>

<% @articles.each do |article| %>
  <h2><%= link_to article.title, article %></h2>
  <p>Published at
    <%= article.created_at.strftime('%b %d, %Y') %>
  </p>
  <p>
    <%= truncate(article.content, length: 200) %>
  </p>
<% end %>

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

  def index

    @articles = Article.search(params[:search])
    @articles = Article.all.order("created_at DESC")

  end

  def new
    @article = current_user.articles.build
  end

  def show
  end

  def create
    @article = current_user.articles.build(article_params)
    if @article.save
      redirect_to @article
    else
      render 'new'
    end
  end

  def edit
  end

  def update
    if @article.update(article_params)
      redirect_to @article
    else
      render 'edit'
    end
  end

  def destroy
    @article.destroy
    redirect_to root_path
  end


  private

  def article_params
    params.require(:article).permit(:title, :content)
  end

  def find_article
    @article = Article.find(params[:id])
  end
end

class Article < ActiveRecord::Base
  belongs_to :user

  def self.search(search)
    if search
      where(["name LIKE ?", "%#{search}%"])
    else
      all
    end
  end
end

new_user_session GET    /users/sign_in(.:format)       devise/sessions#new
            user_session POST   /users/sign_in(.:format)       devise/sessions#create
    destroy_user_session DELETE /users/sign_out(.:format)      devise/sessions#destroy
           user_password POST   /users/password(.:format)      devise/passwords#create
       new_user_password GET    /users/password/new(.:format)  devise/passwords#new
      edit_user_password GET    /users/password/edit(.:format) devise/passwords#edit
                         PATCH  /users/password(.:format)      devise/passwords#update
                         PUT    /users/password(.:format)      devise/passwords#update
cancel_user_registration GET    /users/cancel(.:format)        devise/registrations#cancel
       user_registration POST   /users(.:format)               devise/registrations#create
   new_user_registration GET    /users/sign_up(.:format)       devise/registrations#new
  edit_user_registration GET    /users/edit(.:format)          devise/registrations#edit
                         PATCH  /users(.:format)               devise/registrations#update
                         PUT    /users(.:format)               devise/registrations#update
                         DELETE /users(.:format)               devise/registrations#destroy
                articles GET    /articles(.:format)            articles#index
                         POST   /articles(.:format)            articles#create
             new_article GET    /articles/new(.:format)        articles#new
            edit_article GET    /articles/:id/edit(.:format)   articles#edit
                 article GET    /articles/:id(.:format)        articles#show
                         PATCH  /articles/:id(.:format)        articles#update
                         PUT    /articles/:id(.:format)        articles#update
                         DELETE /articles/:id(.:format)        articles#destroy
                    root GET    /                              articles#index