Modify TimeWithZone#as_json to return 3DP of sub-second accuracy by default, since it's allowed by the spec and is very useful.
Added test:all and test:all:db tasks to speed up full test runs.

Speed up depends on the number of test phases (N) you have for your
app, but it is roughly a 1/N improvement. In my app, it goes from
15.51s to 5.56s.

Inspired by http://ngauthier.com/2012/02/quick-tests-with-bash.html

Reviewed by @tenderlove
Merge pull request #9177 from zenspider/master

Added test:all and test:all:db tasks to speed up full test runs
Update upgrading guide with ActionDispatch::BestStandardsSupport removal
Merge pull request #9178 from robertomiranda/best-standard-support-guide

Update upgrading guide with ActionDispatch::BestStandardsSupport removal [ci skip]
Ignore .ruby-version
Merge pull request #9192 from adammck/ignore-dot-ruby-version

Ignore .ruby-version
Enable hstore extensions on tests if it is not enabled and database supports it
Update .gitignore

Get rid of old .rvmrc and .rbenv-version files.
Fix article for generator name

Use 'some' instead of 'a/an'.
ruby constant syntax is not supported as routing `:controller` option.

The current implementation only works correctly if you supply the `:controller`
with directory notation (eg. `:controller => 'admin/posts'`).

The ruby constant notation (eg. `:controller => 'Admin::Posts`) leads to unexpected problems with `url_for`.

This patch prints a warning for every non supported `:controller` option. I also added documentation how
to work with namespaced controllers. The warning links to that documentation in the rails guide.
Merge pull request #9039 from senny/warn_on_controller_option_with_ruby_constant_syntax

ruby constant syntax is not supported as routing `:controller` option.
Update actionpack/CHANGELOG.md

[ci skip]
Merge pull request #9128 from jamesotron/iso8601-sub-second-accuracy

Modify TimeWithZone#as_json to return 3DP of sub-second accuracy.
Update changelog from #9128 with author name

And improve AS changelog a bit [ci skip]
Add some tests to enumerate how extensions should be stored in the schema output
improve tests to check for existence of extensions method, and skip testing dumped extensions if they are unsupported by the database
add ActiveRecord::AbstractAdapter#extensions and ActiveRecord::ConnectionAdapters::PostgreSQLAdapter#extensions to allow dumping of enabled extensions to schema.rb, add ActiveRecord::SchemaDumper#extensions to dump extensions to schema.rb
Merge pull request #9203 from jaggederest/dumping_pgsql_extensions

Adding database extension support to schema.rb
Add changelog entry for #9203 about schema dumper with db extensions

[ci skip]