Add UX reviewer/maintainer to Danger bot

danger/roulette/Dangerfile

@@ -123,3 +123,22 @@ if changes.any?
   unknown = changes.fetch(:unknown, [])
   markdown(UNKNOWN_FILES_MESSAGE + helper.markdown_list(unknown)) unless unknown.empty?
 end
+
+# Ensure to spin for ux reviewer/maintainer when ~ux is applied (e.g. to review design implementations)
+categories << :ux if helper.gitlab_helper&.mr_labels&.include?('ux') && !categories.include?(:ux)
+
+if changes.any?
+  project = helper.project_name
+
+  random_roulette_spins = roulette.spin(project, categories, timezone_experiment: false)
+
+  rows = random_roulette_spins.map do |spin|
+    markdown_row_for_spins(spin.category, [spin])
+  end
+
+  markdown(MESSAGE)
+  markdown(CATEGORY_TABLE_HEADER + rows.join("\n")) unless rows.empty?
+
+  unknown = changes.fetch(:unknown, [])
+  markdown(UNKNOWN_FILES_MESSAGE + helper.markdown_list(unknown)) unless unknown.empty?
+end