app/views/certificates/_form.html.erb
<%= form_for(@certificate) do |f| %>
<%= render 'shared/error_messages', target: @certificate %>
<%= f.hidden_field :user_id %>
<%= bs_labeled_field("Course", f.collection_select(:course_id, @courses, :id, :name, {}, class: 'form-control')) %>
<%= bs_labeled_field("Full name", f.text_field(:name, class: 'form-control')) %>
<div class="actions">
<%= f.submit 'Create', class: "btn btn-primary"%>
</div>
<% end %>