app/views/projects/_search_bar.html.erb
<%= form_tag project_search_path, method: 'get' do %>
<div class="input-group">
<%= text_field_tag "q", @q, placeholder: 'Search datasets',
class: 'form-control' %>
<span class=input-group-btn>
<%= button_tag type: 'submit', class: 'btn btn-primary' do %>
<i class="glyphicon glyphicon-search"> </i>
<% end %>
</span>
</div>
<% end %>