app/views/shared/_search_form.html.erb
<div class="search-form col-xs-12 col-sm-12 col-md-12 col-lg-12">
<%= form_tag search_path, method: :get, role: "search" do %>
<div class="form-group">
<div class="input-group">
<%= text_field_tag :q, params[:q], placeholder: "Search ARKs", id: "search-q", class: "form-control" %>
<div class="input-group-btn">
<button class="btn btn-default btn-primary" title="Search" type="submit">
<i class="fa fa-search" aria-hidden="true"></i> Search
</button>
</div>
</div>
</div>
<% end %>
</div>