Do not depend on the default parameter being set in Person#initialize.

 ActiveRecord 5.2.x occasionally calls with a nil parameter explicitly provided, so using default arguments does not work.

app/models/person.rb

@@ -185,6 +185,8 @@ class Person < ApplicationRecord
   #   end
   # will not work!  The nil profile will be overriden with an empty one.
   def initialize(params={})
+    params = {} if params.nil?
+
     profile_set = params.has_key?(:profile) || params.has_key?("profile")
     params[:profile_attributes] = params.delete(:profile) if params.has_key?(:profile) && params[:profile].is_a?(Hash)
     super