app/views/user_has_roles/_form.html.erb
<%= form_for(@user_has_role) do |f| %>
<%= f.error_messages -%>
<div class="field">
<%= f.label :user_id %><br />
<%= f.text_field :user_id %>
</div>
<div class="field">
<%= f.label :role_id %><br />
<%= f.text_field :role_id %>
</div>
<div class="actions">
<%= f.submit :disable_with => t(page.saving) %>
</div>
<% end %>