Render menus for current site only

Menus should be rendered for current site only.

Closes #1734

app/helpers/alchemy/pages_helper.rb

@@ -188,7 +188,7 @@ def render_navigation(options = {}, html_options = {})
     # @param [String] - Name of the menu
     # @param [Hash] - A set of options available in your menu partials
     def render_menu(name, options = {})
-      root_node = Alchemy::Node.roots.find_by(name: name)
+      root_node = Alchemy::Node.roots.find_by(name: name, site: Alchemy::Site.current)
       if root_node.nil?
         warning("Menu with name #{name} not found!")
         return

spec/helpers/alchemy/pages_helper_spec.rb

@@ -73,6 +73,18 @@ module Alchemy
       context 'if menu does not exist' do
         it { is_expected.to be_nil }
       end
+
+      context 'with multiple sites' do
+        let!(:site_2) { create(:alchemy_site, host: 'another-site.com') }
+        let!(:menu) { create(:alchemy_node, name: name, site: Alchemy::Site.current) }
+        let!(:node) { create(:alchemy_node, parent: menu, url: '/default-site') }
+        let!(:menu_2) { create(:alchemy_node, name: name, site: site_2) }
+        let!(:node_2) { create(:alchemy_node, parent: menu_2, site: site_2, url: '/site-2') }
+
+        it 'renders menu from current site' do
+          is_expected.to have_selector('ul.nav > li.nav-item > a.nav-link[href="/default-site"]')
+        end
+      end
     end
 
     describe "#render_navigation" do