app/views/kaminari/_page.html.erb
<% if page.current? %>
<li class='active'>
<%= content_tag :a, page, remote: remote, rel: (page.next? ? 'next' : (page.prev? ? 'prev' : nil)) %>
</li>
<% else %>
<li>
<%= link_to page, url, remote: remote, rel: (page.next? ? 'next' : (page.prev? ? 'prev' : nil)) %>
</li>
<% end %>