app/views/links/_nested_links.html.erb
<%= f.hidden_field :id %>
<%= f.label :links, t("links.nested_links.title") %>
<p class="help-text"><%= t("links.nested_links.note") %></p>
<div id="nested-links">
<%= f.fields_for :links do |links_builder| %>
<%= render "links/link_fields", f: links_builder %>
<% end %>
</div>
<%= link_to_add_association t("links.nested_links.add_new_link"), f, :links,
partial: "links/link_fields", id: "new_link_button",
data: {
association_insertion_node: "#nested-links",
association_insertion_method: "append"
},
class: "button hollow" %>