Add download for articles

app/controllers/articles_controller.rb

@@ -21,6 +21,12 @@ class ArticlesController < ApplicationController
     end
 
     @articles = Article.undeleted.where(supplier_id: @supplier, :type => nil).includes(:article_category).order(sort)
+
+    if request.format.csv?
+      send_data ArticlesCsv.new(@articles, encoding: 'utf-8').to_csv, filename: 'articles.csv', type: 'text/csv'
+      return
+    end
+
     @articles = @articles.where('articles.name LIKE ?', "%#{params[:query]}%") unless params[:query].nil?
 
     @articles = @articles.page(params[:page]).per(@per_page)

app/views/articles/index.html.haml

@@ -26,6 +26,7 @@
       = link_to t('.new'), new_supplier_article_path(@supplier), remote: true, class: "btn #{'btn-primary' unless @supplier.shared_supplier}"
       = link_to t('.edit_all'), edit_all_supplier_articles_path(@supplier), class: 'btn'
       = link_to t('.upload'), upload_supplier_articles_path(@supplier), class: 'btn'
+      = link_to t('.download'), supplier_articles_path(@supplier, format: :csv), class: 'btn'
       - if current_user.role_orders?
         = link_to t('.new_order'), new_order_path(supplier_id: @supplier), class: 'btn'