Difference bw `rails new myapp -O` and `rails new myapp` for Rails 4.2.1

gistfile1.txt

diff -r tmp1/myapp/config/application.rb tmp2/myapp/config/application.rb
3,12c3
< require "rails"
< # Pick the frameworks you want:
< require "active_model/railtie"
< require "active_job/railtie"
< # require "active_record/railtie"
< require "action_controller/railtie"
< require "action_mailer/railtie"
< require "action_view/railtie"
< require "sprockets/railtie"
< require "rails/test_unit/railtie"
---
> require 'rails/all'
30a22,24
> 
>     # Do not swallow errors in after_commit/after_rollback callbacks.
>     config.active_record.raise_in_transactional_callbacks = true
Only in tmp2/myapp/config: database.yml
diff -r tmp1/myapp/config/environments/development.rb tmp2/myapp/config/environments/development.rb
21a22,24
>   # Raise an error on page load if there are pending migrations.
>   config.active_record.migration_error = :page_load
> 
diff -r tmp1/myapp/config/environments/production.rb tmp2/myapp/config/environments/production.rb
75a76,78
> 
>   # Do not dump schema after migrations.
>   config.active_record.dump_schema_after_migration = false
diff -r tmp1/myapp/config/initializers/wrap_parameters.rb tmp2/myapp/config/initializers/wrap_parameters.rb
9a10,14
> 
> # To enable root element in JSON for ActiveRecord objects.
> # ActiveSupport.on_load(:active_record) do
> #  self.include_root_in_json = true
> # end
diff -r tmp1/myapp/Gemfile tmp2/myapp/Gemfile
5a6,7
> # Use sqlite3 as the database for Active Record
> gem 'sqlite3'
diff -r tmp1/myapp/.gitignore tmp2/myapp/.gitignore
9a10,13
> # Ignore the default SQLite database.
> /db/*.sqlite3
> /db/*.sqlite3-journal
> 
diff -r tmp1/myapp/test/test_helper.rb tmp2/myapp/test/test_helper.rb
5a6,8
>   # Setup all fixtures in test/fixtures/*.yml for all tests in alphabetical order.
>   fixtures :all
>