Rails assets compile application.js file on Heroku

I have couple of vendor js files and I put them in the application.html.erb of bottom of body tag as;

  <!DOCTYPE html>
    <html>
      <head>
        <meta http-equiv="content-type" content="text/html;charset=UTF-8" />
        <meta charset="utf-8" />
        <title><%= full_title(yield(:title)) %></title>
        <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />

        <meta name="apple-mobile-web-app-capable" content="yes">
        <meta name="apple-touch-fullscreen" content="yes">
        <meta name="apple-mobile-web-app-status-bar-style" content="default">
        <meta content="" name="description" />
        <meta content="" name="author" />
        <%= stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track' => true %>
        <meta name="viewport" content="initial-scale = 1.0,maximum-scale = 1.0" />


      <%= javascript_include_tag 'application', 'data-turbolinks-track' => true %>    





        <%= csrf_meta_tags %>

      </head>

      <% if (controller.controller_name == "main") %>
        <body class="fixed-header no-header">
   ...

      <%= javascript_include_tag 'pace/pace.min', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'modeizr.custom', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'jquery-ui/jquery-ui.min', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'boostrapv3/js/bootstrap.min', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'jquery/jquery-easy', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'jquery-unveil/jquery.unveil.min', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'jquery-bez/jquery.bez.min', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'jquery-ios-list/jquery.ioslist.min', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'jquery-actual/jquery.actual.min', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'jquery-scrollbar/jquery.scrollbar.min', 'data-turbolinks-track' => true %>    
      <%= javascript_include_tag 'bootstrap-select2/select2.min', 'data-turbolinks-track' => true %>    

...       
      </body>
    </html>

Then I declared them for Rails to be able compile (config/initializers/assets.rb)

Rails.application.config.assets.precompile += %w( pace/pace.min.js modeizr.custom.js jquery-ui/jquery-ui.min.js boostrapv3/js/bootstrap.min.js jquery/jquery-easy.js jquery-unveil/jquery.unveil.min.js jquery-bez/jquery.bez.min.js jquery-ios-list/jquery.ioslist.min.js jquery-actual/jquery.actual.min.js jquery-scrollbar/jquery.scrollbar.min.js bootstrap-select2/select2.min.js switchery/js/switchery.min.js ...)

Then I have signup to heroku and created an app then I typed;

1. bundle exec rake assets:precompile RAILS_ENV=production
2. git add .
3. git commit -m "smth"
4. git push heroku master 

app works fine but the problem is in the network tab. I have application.js file but I have all the vendor js files individually. Should not be rails compiling them to 1 file ?