Changes and improvements to the process.

blog/app/models/application_record.rb

@@ -0,0 +1,3 @@
+class ApplicationRecord < ActiveRecord::Base
+  self.abstract_class = true
+end

blog/app/models/article.rb

@@ -0,0 +1,4 @@
+class Article < ApplicationRecord
+  validates :title, presence: true,
+                    length: { minimum: 5 }
+end