app/views/users/new.html.erb
<section class="sign-up"
<% unless request.xhr? %>
data-components="modal"
data-modal-options="<%= {autoload: true, prevent_close: true }.to_json %>"
<% end %> >
<header>
<h1><%= t 'users.signup' %></h1>
</header>
<%= render 'users/signup_form', user: @user %>
</section>