* cache `o.name` value
* Avoid extra `concat` call
* Avoid extra `<<` call

These comments will likely be outdated with time and doesn't include
any information that can't be found in the adapters

Also improve some of the code conventions

Create indexes inline in CREATE TABLE for MySQL

[ci skip] Fix Pull Request URL in 4.1 release note.

Also:
  - updates tests by stubbing table_exists? method
  - adds entry for creating indexes in CREATE TABLE to changelog

This is important, because adding an index on a temporary table after
it has been created would commit the transaction

Conflicts:
	activerecord/CHANGELOG.md

[ci skip]

Still touch associations when theres no timestamp

This reverts commit 6e3ab3e1, reversing
changes made to 39e07b64.

Conflicts:
	activerecord/CHANGELOG.md
	activerecord/test/cases/autosave_association_test.rb

Generating proper migration when ActiveRecord::Base.pluralize_table_names = false

  ActiveRecord::Base.pluralize_table_names = false.

  Previously, generation a migration like this:

      rails g migration add_column_name_to_user name

  would not generating the correct table name.

Fixes #13426.

Support the options methods in tests

Conflicts:
	actionpack/CHANGELOG.md
	activerecord/CHANGELOG.md
	activesupport/CHANGELOG.md
	railties/CHANGELOG.md

arel methods are not supposed to be public API for ActiveRecord

This abstracts us from the actual construction of the nodes

Rename method and stop passing unused arguements.

Fix date_select with_css_classes: true option overwriting other html classes

with_css_classes: true option overwrites other html classes.
Concatenate day month and year classes rather than overwriting.

- Rename `increment_or_decrement` to an apt `set_cache_value` since it actually doesn't increment/decrement in localstore.

If the sqlite file name change in future version we this regexp should
catch

Skip sqlite3 files in .gitignore if no sqlite3 in app

Clean up tables after each test.

Adding active_model in Rails::Info

Incorrect values being printed by assert_select.

Follow-Up to https://github.com/rails/rails/pull/14400

This ensures that all tables are removed after each test and thereby
allowing us to run the tests in a random order.