aardbei/app/views/people/_form.html.erb

<%= form_for(person) do |f| %>
  <% if person.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(person.errors.count, "error") %> prohibited this person from being saved:</h2>

      <ul>
      <% person.errors.full_messages.each do |message| %>
        <li><%= message %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="actions">
    <div class="form-group">
      <%= f.label :first_name %>
      <%= f.text_field :first_name, class: 'form-control' %>
      <%= f.label :infix %>
      <%= f.text_field :infix, class: 'form-control' %>
      <%= f.label :last_name %>
      <%= f.text_field :last_name, class: 'form-control' %>
    </div>
    <div class="form-group">
      <%= f.label :email %>
      <%= f.email_field :email, class: 'form-control' %>
    </div>
    <div class="form-group">
      <%= f.label :birth_date %>
      <%= f.date_field :birth_date, type: 'date', class: 'form-control' %>
    </div>
    <% unless defined? no_admin %>
      <div class="form-group">
        <%= f.check_box :is_admin %>
        <%= f.label :is_admin %>
      </div>
    <% end %>
    <%= f.submit %>
  </div>
<% end %>