Add rake test description

No behavior change
Simplify code in AS json encoder
Changed update_record to use prepared statements.
clarify singular and plural routes

Found the wording on line 158 somewhat confusing. Added short example to clarify.
Update guides/source/active_record_querying.md

Fix missing `ORDER BY id ASC` for Client.first(2);
Uppercase the little y in the SQL equivalent of the Client.last(2).
Fix bug in code example from layouts and rendering guide

The code in 2.3.2 assumed that render has an alert option like
redirect_to to create a flash alert message, but it doesn't.
Corrected link anchor and added colons for continuity
improve grammar describing ActionDispatch::Cookies::CookieJar#delete
improve grammar describing ActionDispatch::Cookies::CookieJar#delete
Update the "upgrading" guide for people coming from 3.0 and 3.1. The latest versions for 3.1 and 3.2 are now 3.2.12 and 3.1.11 respectively.
Extract dependency tracking from Digestor
Allow registering custom dependency trackers
Use a thread safe hash
Return an empty array if no tracker is found
Rename ErbTracker to ERBTracker
Register trackers on extensions, not handlers
Add more documentation for create_join_table.

Explain that it doesn't create indices by default and
that it also has a block form.
Fix warning
Indent comment block by two spaces.

As requested by @fxn
https://github.com/schuetzm/rails/commit/743d15bba182df80d003d205690ead988970299c#commitcomment-2661417
remove uncommented railties boot_test.rb