bootstrap dropdown login form in haml

layout.haml

.navbar.navbar-fixed-top
      .navbar-inner
        .container-fluid
          %a.btn.btn-navbar{"data-target" => ".nav-collapse", "data-toggle" => "collapse"}
            %span.icon-bar
            %span.icon-bar
            %span.icon-bar
          %a.brand{:href => "#"} appname 
          .nav-collapse
            %ul.nav
              %li.active
                %a{:href => "#"} Home
              %li
                %a{:href => "#about"} About
              %li
                %a{:href => "#contact"} Contact
          - if !@user
            %ul.nav.pull-right
              %li
                %a{:href => "/users/sign_up"} Sign Up
              %li.divider-vertical
              %li.dropdown
                %a{:href=>"#", :class=>"dropdown-toggle", "data-toggle"=>"dropdown"}Sign In <b class="caret"></b>
                %div.dropdown-menu{:style=>"padding:15px;padding-bottom:0px;"}
                  %form{"accept-charset" => "UTF-8", :action => "/login", :method => "post"}
                    %input#username{:name => "username", :size => "30", :style => "margin-bottom: 15px;", :type => "text"}/
                    %input#password{:name => "password", :size => "30", :style => "margin-bottom: 15px;", :type => "password"}/
                    %input#remember_me{:name => "remember_me", :style => "float: left; margin-right: 10px;", :type => "checkbox", :value => "1"}/
                    %label.string.optional{:for => "remember_me"} Remember me
                    %input.btn.btn-primary{:name => "commit", :style => "clear: left; width: 100%; height: 32px; font-size: 13px;", :type => "submit", :value => "Sign In"}