app/views/geographic_areas/_search.erb
<%= form_tag search_geographic_areas_path do %>
<div class="field">
<%= label_tag 'with name like' %><br>
<%= search_field_tag :name %>
</div>
<div class="actions">
<%= submit_tag 'Search' %>
</div>
<% end %>
<%= content_tag(:div, "Previous search: '#{@search_string}'") if @search_string -%>