link_to_add make large index number

[shingo-nakanishi]

version

0.3.2

no support index

<tbody id="foo">
  <%= f.fields_for :foos, wrapper: false do |of| -%>
    <tr class="fields">
      <td><%= of.index %></td> 

click link_to_add make 1451347938120
next click link_to_add make 1451347952296

Rails4 support index

http://stackoverflow.com/a/22640703/1979953