Rails checkbox form

_form.html.erb

<%= form_with(model: user_group, local: true) do |form| %>
  <% if user_group.errors.any? %>
    <div id="error_explanation" class="alert alert-danger">
      <h5><%= pluralize(user_group.errors.count, "error") %> prohibited this user group from being saved:</h5>

      <ul>
      <% user_group.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="">
    <%= form.hidden_field :account_id, value: current_user&.account&.id %>
  </div>

  <div class="form-group">
    <%= form.label :name %>
    <%= form.text_field :name, class: 'form-control' %>
  </div>

  <div class="form-group">
    <%= form.label :desc %>
    <%= form.text_field :desc, class: 'form-control' %>
  </div>

  <div class="form-group">
      <table class="table">
        <thead>
          <th>Resource name</th>
          <th>Actions</th>
        </thead>
        <tbody>
          <%= form.fields_for :permissions do |form| %>
           <%= render "permission_fields", form: form %>
          <% end %>
        </tbody>
      </table>
  </div>

  <div class="form-group">
    <% if user_group.persisted? %>
      <div class="float-right">
        <%= link_to 'Destroy', user_group, method: :delete, class: "text-danger", data: { confirm: 'Are you sure?' } %>
      </div>
    <% end %>

    <%= form.submit class: 'btn btn-primary' %>

    <% if user_group.persisted? %>
      <%= link_to "Cancel", user_group, class: "btn btn-link" %>
    <% else %>
      <%= link_to "Cancel", user_groups_path, class: "btn btn-link" %>
    <% end %>
  </div>
<% end %>

_permission_fields.html.erb

<tr>
  <td> <%= form.text_field :controller_name %> </td>
  <td>
     <%= form.fields_for :actions do |field|%>
        index<%= field.check_box :index %>
        show<%= field.check_box :show %>
     <% end %>
   </td>
</tr>

user_group.rb

class UserGroup < ApplicationRecord
  belongs_to :account
  has_many   :permissions, dependent: :destroy
  validates  :desc, presence: true
  validates  :name, presence: true, uniqueness: true

  accepts_nested_attributes_for :permissions, allow_destroy: true
end