<div class="filter-form">
  <div class="inner-block">
    <p>You can use the filters to show only cases that match your interests</p>

    <%= form_tag({}, method: :get, class: 'facet-menu') do %>
      <%= render facet_collection.facets %>
      <input type="submit" value="Filter results" class="button" />
    <% end %>
  </div>
</div>

<div class="filter-form">
  <div class="inner-block">
    <p>You can use the filters to show only cases that match your interests</p>

    <form method="get" action="" class="facet-menu">
      <%= render facet_collection.facets %>
      <input type="submit" value="Filter results" class="button" />
    </form>
  </div>
</div>

Use form tag rather than rails helper method
Use form tag rather than rails helper method

The Rails helper method adds a UTF8 field which submits a UTF8 tick.
This is to trick older versions of IE to send UTF8 POST data. As this is
a GET form it doesn't make any sense and can cause errors when people
copy and paste urls.
