Do not try to write timestamps if they are missing #8813
[ci skip] Mention the change in nil handling for serialized attributes
in "Upgrading from Rails 3.2 to Rails 4.0"
[ci skip] Clarify the "Serialized Attributes" section

Mention that the change in nil handling for serialized attributes
affects custom coders.
Fixes test for Gemfile entry changes

Broken by fbe38c9e9d4fe9f82518e8ffc1d757459b0c5f1c
Merge pull request #16429 from arunagw/aa-build-fix-gemfile-spring

Fixes test for Gemfile entry changes
add a test for prepending SCRIPT_NAME to generated urls
save a hash allocation per request.
Add config option for cookies digest

You can now configure custom digest for cookies in the same way as `serializer`:

config.action_dispatch.cookies_digest = \SHA256'
Return preconfigured AS::MessageVerifier
Merge pull request #16434 from strzalek/cookies-digest-config-option

Add digest config option for SignedCookiesJar
Revert "Merge pull request #16434 from strzalek/cookies-digest-config-option"

This reverts commit 705977620539e2be6548027042f33175ebdc2505, reversing
changes made to dde91e9bf5ab246f0f684b40288b272f4ba9a699.

IT BROKE THE BUILD!!!
Docs: grammar fix for fetch. [ci skip]
Merge pull request #16437 from mscoutermarsh/master

Docs: grammar fix for fetch. [ci skip]
Using delegated connection method
Pass block for logging.

This follows the good practice listed on http://guides.rubyonrails.org/debugging_rails_applications.html#impact-of-logs-on-performance.
[ci skip] Changed options to +options+ for rdoc
Update README.md

Ruby on Rails Tutorial link updated.
Merge pull request #16443 from duccioarmenise/patch-1

Rails Tutorial link updated
Merge pull request #16439 from voxxit/patch-1

Using delegated connection method
Merge pull request #16440 from tgxworld/pass_log_in_block

Pass block for logging.