Add help link to header.

app/views/layouts/_head_panel.html.haml

@@ -20,6 +20,10 @@
             = link_to search_path, title: "Search", class: 'has_bottom_tooltip', 'data-original-title' => 'Search area' do
               %i.icon-search
           %li
+            = link_to help_path, title: 'Help', class: 'has_bottom_tooltip',
+               'data-original-title' => 'Help'  do
+              %i.icon-question
+          %li
             = link_to public_root_path, title: "Public area", class: 'has_bottom_tooltip', 'data-original-title' => 'Public area' do
               %i.icon-globe
           %li