How to use current_page? to do a nav bar in rails

nav.html.erb

<%# This is completely boilerplate rails %>
<ul id="navbar">
  <li><%= link_to_unless_current("Home", home_path) %></li>
  <li><%= link_to_unless_current("About Us", about_path) %></li>
</ul>

<%# More specific %>
<ul id="navbar">
  <li><%= link_to "Home", home_path, :class => current_page?(home_path) ? 'current' : '' %></li>
  <li><%= link_to "About Us", about_path, :class => current_page?(home_path) ? 'current' : '' %></li>
</ul>