obdev/app/views/participants/new.html.erb

<div class="container mt-5">
  <div class="row justify-content-center">
    <div class="col-md-6">
      <h1 class="mb-4 text-center">New Participant</h1>

      <%= render 'form', participant: @participant %>

      <div class="mt-3 text-center">
        <%= link_to 'Back to List', participants_path, class: "btn btn-secondary" %>
      </div>
    </div>
  </div>
</div>