app/views/admin/tags/_form.html.erb
<%= form_for :tag, :url => collection_url, :remote => true do |f| %>
<%= error_messages_for(@tag) %>
<label>Name</label><%= f.text_field :name %><br />
<label>Type</label>
<%= f.select :model, options_for_select(PresetTag::TYPES,
@tag && @tag.model ) %>
<% end %>