# Модель Item
class Item < ApplicationRecord

  has_attached_file :image, styles: { small: '64x64', med: '100x100', large: '200x200' }
  validates_attachment_content_type :image, content_type: /\Aimage\/.*\z/
end

# migrate
class AddImageToItems < ActiveRecord::Migration[5.0]
  def self.up
    change_table :items do |t|
      t.attachment :image
    end
  end

  def self.down
    remove_attachment :items, :image
  end
end

# edit.html.erb
<h1>Edit new item</h1>

<%= form_for @item, html: { multipart: true } do |f|  %>
  <%= render partial: "form", locals: { f: f } %>
  <p></br><%= f.submit "Обновить товар"%></p>
<% end %>

# new.html.erb
<h1>Create new item</h1>

<%= form_for @item, html: { multipart: true } do |f|  %>
  <%= render partial: "form", locals: { f: f } %>
  <p></br><%= f.submit "Создать товар"%></p>
<% end %>

#index.html.erb
<h1>Items</h1>

<% if @items.empty? %>
  <b>No items in store</b>
<% else %>
  <table>
    <tr>
      <th>item id</th>
      <th>Name</th>
      <th>Price</th>
      <th>Описания</th>
      <th>Дата создания товара</th>
      <th></th>
      <th>Рейтинг</th>
      <th>Image</th>
    </tr>

    <% @items.each do |i| %>
      <tr>
        <td><%= i.id %></td>
        <td><%= link_to i.name, item_path(i) %></td>
        <td><%= i.price %> руб.</td>
        <td><%= i.description %></td>
        <td><%= i.created_at.to_s.sub("2016", "2017") %></td>
        <td><%= link_to "Удалить", i, method: :delete, data: {confirm: "Точно удалить?" }%> </td>
        <td>Рейтинг: <%= i.votes_count %>, <%= link_to "+", upvote_item_path(i) %></td>
        <td><%= image_tag  i.image.url(:med) %></td>
      </tr>
    <% end %>
  </table>
<% end %>