问如何使用Rails 3将html表转换为PDF

EN

<h1>Choose the option</h1>
<p>
    <%= link_to "new input",products_new_path %>
</p>
<table>
    <tr>
       <th>Product name</th>
       <th>Product Catagory</th>
    </tr>
    <% @product.each do |p| %>
    <tr>
        <td><%= p.p_name %></td>
        <td><%= p.p_catagory %></td>
    </tr>
    <% end %>
</table>

class ProductsController < ApplicationController
    def index
        @product=Product.all
        respond_to do |format|
           format.html
           format.pdf do
              pdf = Prawn::Document.new
              send_data pdf.render, filename: 'report.pdf', type: 'application/pdf'
            end
        end
    end
    def new
        @product=Product.new
    end
    def create
        @product=Product.new(params[:product])
        if @product.save
            flash[:notice]="Data submitted"
            flash[:color]="valid"
            redirect_to :action => "index"
        else
            flash[:alert]="Data could not finish"
            flash[:color]="invalid"
            render 'new'
        end
    end
end

source 'https://rubygems.org'

gem 'rails', '3.2.19'

# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'

gem 'sqlite3'


# Gems used only for assets and not required
# in production environments by default.
group :assets do
  gem 'sass-rails',   '~> 3.2.3'
  gem 'coffee-rails', '~> 3.2.1'

  # See https://github.com/sstephenson/execjs#readme for more supported runtimes
  # gem 'therubyracer', :platforms => :ruby

  gem 'uglifier', '>= 1.0.3'
end

gem 'jquery-rails'

# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'

# To use Jbuilder templates for JSON
# gem 'jbuilder'

# Use unicorn as the app server
# gem 'unicorn'

# Deploy with Capistrano
# gem 'capistrano'

# To use debugger
# gem 'debugger'
gem 'prawn'

Mime::Type.register "application/pdf", :pdf