_form.html.erb

<% @attachment = @plot.attachments.new %> 
  <%= form_for ([@cemetery, @plot, @attachment]), :class=> "form-horizontal panel", :html => { :multipart => true} do |f| %>
  <div class="panel-body">
  <% if @attachment.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@attachment.errors.count, "error") %> prohibited this attachment from being saved:</h2>

      <ul>
        <% @attachment.errors.full_messages.each do |msg| %>
          <li><%= msg %></li>
        <% end %>
      </ul>
    </div>
  <% end %>

  
    
    <%= f.file_field :photo, multiple: true, name: 'attachment[photo]', :hint=> "You can select multiple files" %>
   
  </div>
  <div class="panel-footer text-right actions">
     <%= f.submit "save", class: 'btn' %>
  </div>
<% end %>

<% # jquery upload template # %>
<script id="template-upload" type="text/x-tmpl"><div class="upload">{%=o.name%}<div class="progress"><div class="progress-bar bar" style="width: 0%"></div></div></div></script>