app/views/admin/user_datas/addresses/new.html.erb
<h2> New Address (<%= customer.name %>) </h2>
<%= form_for @form_address, url: admin_user_datas_user_addresses_path(customer, @form_address) do |f| %>
<%= render partial: 'form', locals: { f: f } %>
<div class="actions"><%= f.submit 'Create' , class: 'button' %></div>
<% end %>
<p><%= link_to "Back to List", admin_user_datas_user_addresses_path(customer), class: 'button' %></p>