Add admin_style_v3 feature toggle

app/views/spree/admin/shared/_head.html.haml

@@ -14,7 +14,11 @@
 
 %link{:href => "https://fonts.googleapis.com/css?family=Open+Sans:400italic,600italic,400,600&subset=latin,cyrillic,greek,vietnamese", :rel => "stylesheet", :type => "text/css"}
 
-= stylesheet_pack_tag 'admin-styles', media: "screen, print"
+- if feature?(:admin_style_v3, spree_current_user)
+  = stylesheet_pack_tag 'admin-style-v3', media: "screen, print"
+- else
+  = stylesheet_pack_tag 'admin-styles', media: "screen, print"
+
 = render "layouts/bugsnag_js"
 = javascript_include_tag 'admin/all'
 

app/webpacker/packs/admin-style-v3.scss

@@ -0,0 +1 @@
+@import "../css/admin_v3/all.scss";

lib/open_food_network/feature_toggle.rb

@@ -11,6 +11,9 @@ module OpenFoodNetwork
     # We way move this to a YAML file when it becomes too awkward.
     # **WARNING:** Features not in this list will be removed.
     CURRENT_FEATURES = {
+      "admin_style_v3" => <<~DESC,
+        Test the work-in-progress design updates.
+      DESC
       "api_reports" => <<~DESC,
         An API endpoint for reports at
         <code>/api/v0/reports/:report_type(/:report_subtype)</code>