pg_namespace table isn't used.

be ignored. A regular expression constraint gets overwritten when the
routes.rb file is processed. Changed the overwriting to an ||= instead
of an = assignment.

Do not instantiate intermediate AR objects when eager loading.

Closes #3313

Locate `=require turbolinks` at the bottom of application.js

Turbolinks should be located at the bottom of application.js
to detect assets change properly.

Ensure original encoding does not change in mb_chars test.

See https://github.com/ruby/ruby/commit/9c1b3161f20162dc1682d758c0e4d2fc3a74745e

All Active Support tests pass in 2.0.0preview2 after this change.
Closes #8409

Override <%== to always behave as literal text rather than toggling based on whether escaping is enabled. Fixes that existing plaintext email templates using <%== unexpectedly flipped to *escaping* HTML when #8235 was merged.

Fix wrong doc and message about rails profiler.

Related to changes introduced in 553b5637

Updates to the Migration Guide

More descriptive error when rendering a partial with `:layout => true`

Add db to the list of default annotation folders

ActiveModel::Errors spec fixes

Quote ~ in git config global excludes command.

This will put ~/ in .gitconfig so it will not be hardcoded to the home
directory where the command was run.

When there are missing components in the Hash returned by
Date._parse only the date components should default to the
value of Time.zone.now, the time components should all
default to zero.

Add Mailer Callback section to Mailer guides

Reset attributes should not report changes.

When resetting an attribute, you expect it to return to the state it was
before any changes. Namely, this fixes this unexpected behavior:

~~~ruby
model.name = "Bob"
model.reset_name!
model.name_changed? #=> true
~~~

This introduces a bunch of editing/re-writing to the migrations guide.
There were a bunch of small changes, and a few larger ones:

* mysql does support transactions.
* Add a section about db/seeds.rb
* Largely re-wrote the first few sections

Validations guide

plus:

* 80 column formats
* replacing the explanation of the dynamic_form gem with the example
  HTML/CSS that Rails scaffolds generate.

Conflicts:
	guides/source/active_record_validations.md