Generate ApplicationRecord if it does not already exist

activerecord/lib/rails/generators/active_record/model/model_generator.rb

@@ -22,11 +22,13 @@ def create_migration_file
 
       def create_model_file
         template 'model.rb', File.join('app/models', class_path, "#{file_name}.rb")
+        generate_application_record
       end
 
       def create_module_file
         return if regular_class_path.empty?
         template 'module.rb', File.join('app/models', "#{class_path.join('/')}.rb") if behavior == :invoke
+        generate_application_record
       end
 
       hook_for :test_framework
@@ -37,6 +39,12 @@ def attributes_with_index
           attributes.select { |a| !a.reference? && a.has_index? }
         end
 
+        def generate_application_record
+          if self.behavior == :invoke && !File.exist?('app/models/application_record.rb')
+            template 'application_record.rb', 'app/models/application_record.rb'
+          end
+        end
+
         # Used by the migration template to determine the parent name of the model
         def parent_class_name
           options[:parent] || determine_default_parent_class

activerecord/lib/rails/generators/active_record/model/templates/application_record.rb

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

railties/test/generators/model_generator_test.rb

@@ -6,6 +6,14 @@ class ModelGeneratorTest < Rails::Generators::TestCase
   include GeneratorsTestHelper
   arguments %w(Account name:string age:integer)
 
+   def test_application_record_skeleton_is_created
+     run_generator
+     assert_file "app/models/application_record.rb" do |record|
+       assert_match(/class ApplicationRecord < ActiveRecord::Base/, record)
+       assert_match(/self.abstract_class = true/, record)
+     end
+   end
+
   def test_help_shows_invoked_generators_options
     content = run_generator ["--help"]
     assert_match(/ActiveRecord options:/, content)