Improve CONTRIBUTING

Noting that we don't take feature requests or 'help me' stuff on the Issues tracker should cut down a ton on bad Issues.

This reverts commit 5d95f320.

log 404 status when ActiveRecord::RecordNotFound was raised (#7646)

Rename .rb template handler to .ruby to avoid conflicts with mustache classes

Allowing pass couple extension to one register_template_handler call

Fix collection= on hm:t join models when unsaved

If assigning to a has_many :through collection against an unsaved
object using the collection=[<array_of_items>] syntax, the join models
were not properly created, previously.

Add missing entry in CHANGELOG about change of AD::Session::MemCacheStore

Remove unncessary code.

Fix build for Queue.

Fix warning: method redefine. Testcase name are duplicated.

Use synchronous queue by default. Separate queued message delivery jobs from the queued message wrappers so the queue itself needn't be marshaled (due to queue reference QueuedMessage).

improve AR/CHANGELOG [ci skip]

Adds migration and type casting support for PostgreSQL Array datatype

Don't preserve SELECT columns on COUNT

Closes #7651

The COUNT clause of a finder_sql relationship is being rewritten from
COUNT(*) to COUNT(table_name.*). This does not appear to be valid syntax
in MySQL:

```
mysql> SELECT COUNT( table_name.* ) FROM `table_name`;
ERROR 1064 (42000): You have an error in your SQL syntax; check the
manual that corresponds to your MySQL server version for the right
syntax to use near '* ) FROM `table_name`' at line 1
```

This fixes the bug, as well as adding tests so we don't re-introduce
it in the future.

Fixes #3956.

Set up config_accessor with a default value by block

* ActiveSupport::Configurable should allow config_accessor to take
  default value by block, just like cattr_accessor.

    class User
      include ActiveSupport::Configurable
      config_accessor :hair_colors do
        [:brown, :black, :blonde, :red]
      end
    end

    User.hair_colors # => [:brown, :black, :blonde, :red]

* remove trailing whitespaces in configurable.rb and its test file.

* Update ActiveSupport CHANGELOG.