Add controller action to destroy a PromotionBatch

app/controllers/spree/admin/promotion_batches_controller.rb

@@ -13,6 +13,21 @@ def update
         super
       end
 
+      def destroy
+        result = Spree::PromotionBatches::Destroy.call(promotion_batch: @promotion_batch)
+
+        if result.success?
+          flash[:success] = flash_message_for(@promotion_batch, :successfully_removed)
+        else
+          flash[:error] = @promotion_batch.errors.full_messages.join(', ')
+        end
+
+        respond_with(@promotion_batch) do |format|
+          format.html { redirect_to location_after_destroy }
+          format.js   { render_js_for_destroy }
+        end
+      end
+
       def csv_export
         send_data Spree::PromotionBatches::PromotionCodesExporter.new(params).call,
                   filename: "promo_codes_from_batch_id_#{params[:id]}.csv",