Add backend support to read and update list-specific show_replies settings

app/controllers/api/v1/lists_controller.rb

@@ -38,6 +38,6 @@ class Api::V1::ListsController < Api::BaseController
   end
 
   def list_params
-    params.permit(:title)
+    params.permit(:title, :replies_policy)
   end
 end

app/serializers/rest/list_serializer.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class REST::ListSerializer < ActiveModel::Serializer
-  attributes :id, :title
+  attributes :id, :title, :replies_policy
 
   def id
     object.id.to_s