deprecating string based terminators
use inject rather than multiple assignments
make the compile method thread safe
only dup the options once, the Callback object does not mutate them
Also support extensions in PostgreSQL 9.1, because this has been supported since 9.1.
Remove unnecessary code, because this extension is created on demand in hstore_test.rb.
ActionMailer::Collector should be nodoc'd
Document ActionMailer::LogSubscriber and ActionMailer::DeliveryMethods::ClassMethods
Document ActionMailer::MailHelper
Removed incorrect warning from application.js templates and replaced it with stub command description
nodoc ActionMailer module from lib/action_mailer/*.rb
Document Rails::Generators::MailerGenerator
Merge pull request #10626 from firedev/master

Removed incorrect warning from application.js templates and replaced it with stub command description
change to destructive `deep_symbolize_keys` after https://github.com/rails/rails/commit/df24b8790f22384a068fece7042f04ffd2fcb33e which allows to do so. This helps to avoid extra hash object creation, by symbolizing inplace
Added documentation for ActiveRecord::Associations::Builder::Association class
Fixes bug 10628.
Added some more documentation for ActiveRecord::Associations::Builder::Association class
Added some more documentation for define_readers and define_writer of the Association and its inherited classes
restore ability to return nil from asset_host proc, add test
Rewrite `activerecord/RUNNING_UNIT_TESTS`

`RUNNING_UNIT_TESTS` is written in an unclear and confusing manner. This commit
attempts to correct that.

Thanks to zzak and vipulnsward for feedback.