Inherit models from ApplicationRecord instead of ActiveRecord::Base.

app/models/news_update.rb

@@ -1,4 +1,4 @@
-class NewsUpdate < ActiveRecord::Base
+class NewsUpdate < ApplicationRecord
   belongs_to :creator, :class_name => "User"
   belongs_to :updater, :class_name => "User"
   scope :recent, lambda {where("created_at >= ?", 2.weeks.ago).order("created_at desc").limit(5)}