rails 4 bootstrap 3 collapsable navbar -

sorry newbie question, can see i'm doing wrong? followed directions on bootstrap website, , unable create collapsing navbar in web app. list items under ="nav pull-right" won't collapse when decrease width of window. think maybe because don't have collapse plugin in bootstrap.js. issue?

<%= link_to "catalyst", users_path, class: "brand" %>  <header class="navbar navbar-fixed-top navbar-inverse">   <div class="navbar-inner">     <div class="container">        <a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">         <span class="icon-bar"></span>         <span class="icon-bar"></span>         <span class="icon-bar"></span>       </a>       <%= link_to "webapp", users_path, class: "brand" %>       <div class="nav-collapse collapse">         <ul class="nav pull-right">           <li><%= link_to current_user.full_name, current_user %></li>           <li id="fat-menu" class="dropdown">             <a href="#" class="dropdown-toggle" data-toggle="dropdown">             mailbox                <% if unread_count > 0 %>                 (<%= unread_count %>)               <% end %>               <b class="caret"></b>             </a>             <ul class="dropdown-menu">               <li><%= link_to "received", messages_path %></li>               <li><%= link_to "sent", sent_messages_path %></li>             </ul>           </li>           <li><%= link_to "sign out", destroy_user_session_path, :method => :delete %></li>         </ul>       </div>     </div>   </div> </header> 

change <div class="nav-collapse collapse"> <div class="navbar-collapse collapse">