We will support only Ruby >= 2.1.

But right now we don't accept pull requests with syntax changes to drop
support to Ruby 1.9.

4.2 release notes pass [skip ci]

Adds preloaded_records method to NullPreloader - fixes #16070

This fixes a regression where preloading association throws an
exception if one of the associations in the preloading hash doesn't
exist for one record.

Fixes #16070

Fixed a bug where AR::RecordNotSaved loses the given error message

Remove ecosystem link from guides

Refactor `SchemaCreation#visit_AddColumn`

Change originated from https://github.com/rails/rails/pull/17739#issuecomment-64829088

/cc @metaskills

Since 3e30c5d4, it started ignoring the given error message. This commit
changes the behavior of AR::RecordNotSaved#initialize so that it no
longer loses the given error message.

Correct test description for large integer test

This reverts commit 2a4e14db.

Update cookies.rb
Conflicts:
	actionpack/lib/action_dispatch/middleware/cookies.rb

[ci skip] Remove outdate note of :dependent in guide

Clarification follow-up to e2cce6cd [ci skip]

[skip ci]

Action Mailer change log pass [ci skip]

[skip ci]

It should not be used in applications

Fix format "Form Helpers" guide

The `"_tag"` was interpreted as the start of a italics.

Fix typo in Rails 4.2 release notes

Documentation regression in JSON#from_json

Allow authentication header to not have to specify 'token=' key.

Code style changes for various activerecord errors