Define a serializer for /api/v1/mutes/details

app/serializers/rest/mute_serializer.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class REST::MuteSerializer < ActiveModel::Serializer
+  include RoutingHelper
+  
+  attributes :id, :account, :target_account, :created_at, :hide_notifications
+
+  def account
+    REST::AccountSerializer.new(object.account)
+  end
+
+  def target_account
+    REST::AccountSerializer.new(object.target_account)
+  end
+end