Introduce ApplicationRecord, an Active Record layer supertype

It's pretty common for folks to monkey patch `ActiveRecord::Base` to
work around an issue or introduce extra functionality. Instead of
shoving even more stuff in `ActiveRecord::Base`, `ApplicationRecord` can
hold all those custom work the apps may need.

Now, we don't wanna encourage all of the application models to inherit
from `ActiveRecord::Base`, but we can encourage all the models that do,
to inherit from `ApplicationRecord`.

Newly generated applications have `app/models/application_record.rb`
present by default. The model generators are smart enough to recognize
that newly generated models have to inherit from `ApplicationRecord`,
but only if it's present.

2 files changed, 2 insertions, 1 deletions

diff --git a/railties/test/application/configuration_test.rb b/railties/test/application/configuration_test.rb
index 25e749ac14..87e28288ee 100644
--- a/railties/test/application/configuration_test.rb
+++ b/railties/test/application/configuration_test.rb
@@ -228,6 +228,7 @@ module ApplicationTests
     end
 
     test "the application can be eager loaded even when there are no frameworks" do
+      FileUtils.rm_rf("#{app_path}/app/models/application_record.rb")
       FileUtils.rm_rf("#{app_path}/config/environments")
       add_to_config <<-RUBY
         config.eager_load = true
diff --git a/railties/test/application/rake_test.rb b/railties/test/application/rake_test.rb
index 0da0928b48..1b009e0742 100644
--- a/railties/test/application/rake_test.rb
+++ b/railties/test/application/rake_test.rb
@@ -98,7 +98,7 @@ module ApplicationTests
     end
 
     def test_code_statistics_sanity
-      assert_match "Code LOC: 7     Test LOC: 0     Code to Test Ratio: 1:0.0",
+      assert_match "Code LOC: 10     Test LOC: 0     Code to Test Ratio: 1:0.0",
         Dir.chdir(app_path){ `bin/rake stats` }
     end