Add members flyout on collapsed sidebar

app/views/layouts/nav/sidebar/_project.html.haml

@@ -272,6 +272,11 @@
               = sprite_icon('users')
             %span.nav-item-name
               Members
+          %ul.sidebar-sub-level-items.is-fly-out-only
+            = nav_link(path: %w[members#show], html_options: { class: "fly-out-top-item" } ) do
+              = link_to project_settings_members_path(@project) do
+                %strong.fly-out-top-item-name
+                  #{ _('Members') }
       = render 'shared/sidebar_toggle_button'