nested_form + bootstrapでネストしたモデルの入力フォームをタブ表示する ref: http://qiita.com/h-sakano/items/3f7c253b461aa9cfc7ab

_form.html.erb

<%= bootstrap_nested_form_for(@model_a, layout: :horizontal, label_col: "col-xs-2", control_col: "col-xs-10") do |f| %>
  <%= f.text_field :column_a, label: "カラムA" %>
  <%= f.text_field :column_b, label: "カラムB" %>
  .
  .
  .
  <ul class="nav nav-tabs" role="tablist" id="model-b-tab-list">
  </ul>

  <div class="tab-content" id="model-b-tab-contents">
    <%= f.fields_for :nested_model_tables, wrapper: false do |nf| %>
      <div class="tab-pane fields" role="tabpanel">
        <%= nf.text_field :column_a, label: "カラムA" %>
        <%= nf.text_field :column_b, label: "カラムB" %>
        .
        .
        .
      </div>
      <!-- link_to_addを呼び出したいだけで、出力結果は使用しないので、<%= %>ではなくて<% %>で囲む。 -->
      <% f.link_to_add "タブ追加", :part_number_sequences, data: { target: "#model-b-tab-contents" } %>
    <% end %>
  </div>
<% end %>

model_a.coffee

$ ->
  $(document).on 'ready', ->
    nested_form_tab('model-b-tab-list', 'model-b-tab-contents', 'タブ', '<i class="glyphicon glyphicon-plus"></i>', 'nested_model_tables')
    $("#model-b-tab-contents").children('div').first().addClass('active')

  $(document).on 'nested:fieldAdded:nested_model_tables', (event) ->
    nested_form_tab('model-b-tab-list', 'model-b-tab-contents', 'タブ', '<i class="glyphicon glyphicon-plus"></i>', 'nested_model_tables')
    $("#model-b-tab-contents").children('div').removeClass('active')
    event.field.addClass('active')

  nested_form_tab = (target_ul_id, target_div_id, tab_name_prefix, add_tab_name, assoc) ->
    $("##{target_ul_id}").empty()
    for value, index in $("##{target_div_id}").children('div')
      $(value).attr('id', "#{target_div_id}-#{index + 1}")
      $("##{target_ul_id}").append($("<li role='presentation'><a aria-controls='#{target_div_id}-#{index + 1}' href='##{target_div_id}-#{index + 1}' data-toggle='tab' role='tab'>#{tab_name_prefix}#{index + 1}</a></li>"))
    $("##{target_ul_id}").append($("<li role='presentation'><a data-target='##{target_div_id}' class='add_nested_fields' data-association='#{assoc}' data-blueprint-id='#{assoc}_fields_blueprint' href='javascript:void(0)'>#{add_tab_name}</a></li>"))