Epic Boards - Add Boards navigation item under Epics

ee/app/views/layouts/nav/ee/_epic_link.html.haml

 - return unless group_sidebar_link?(:epics)
 
 - epics_count = group_epics_count(state: 'opened')
-- epics_items = ['epics#show', 'epics#index', 'roadmap#show']
+- epics_items = ['epics#show', 'epics#index', 'epic_boards#index', 'epic_boards#show', 'roadmap#show']
 
 = nav_link(path: epics_items) do
   = link_to group_epics_path(group), class: 'qa-group-epics-link' do
@@ -20,6 +20,11 @@
       = link_to group_epics_path(group), title: 'List' do
         %span= _('List')
 
+    - if Feature.enabled?(:epic_boards, @group)
+      = nav_link(path: 'epic_boards#show', html_options: { class: "#{active_when(params[:board_type] == 'epic') } home" }) do
+        = link_to group_boards_path(group, board_type: "epic"), title: 'Boards' do
+          %span= _('Boards')
+
     = nav_link(path: 'roadmap#show', html_options: { class: 'home' }) do
       = link_to group_roadmap_path(group), title: 'Roadmap' do
         %span= _('Roadmap')

ee/config/routes/group.rb

@@ -112,6 +112,10 @@ constraints(::Constraints::GroupUrlConstrainer.new) do
         resources :notes, only: [:index, :create, :destroy, :update], concerns: :awardable, constraints: { id: /\d+/ }
       end
 
+      collection do
+        resources :boards, only: [:index, :show], as: 'epic_boards'
+      end
+
       collection do
         post :bulk_update
       end

ee/spec/features/groups/navbar_spec.rb

@@ -66,6 +66,7 @@ RSpec.describe 'Group navbar' do
   context 'when epics are available' do
     before do
       stub_licensed_features(epics: true)
+      stub_feature_flags(epic_boards: false)
 
       insert_after_nav_item(
         _('Group overview'),
@@ -84,6 +85,28 @@ RSpec.describe 'Group navbar' do
     it_behaves_like 'verified navigation bar'
   end
 
+  context 'when epics and epic boards are available' do
+    before do
+      stub_licensed_features(epics: true)
+
+      insert_after_nav_item(
+        _('Group overview'),
+        new_nav_item: {
+          nav_item: _('Epics'),
+          nav_sub_items: [
+            _('List'),
+            _('Boards'),
+            _('Roadmap')
+          ]
+        }
+      )
+
+      visit group_path(group)
+    end
+
+    it_behaves_like 'verified navigation bar'
+  end
+
   context 'when the logged in user is the owner' do
     before do
       group.add_owner(user)