In Rails 4.0, json decoding relied on MultiJson. This changed from 4.1
forward since it reached its end of life, and this extra argument was
kept for compatibility. We are safe to remove it now.

Remove call to sanitize_sql_hash_for_conditions

This can resolve confusing situation when a top level constant exists
but a namespaced version is identified.

Related to #19531.

Merge branch 'sti-subclass-from-attributes' of https://github.com/agrobbin/rails into agrobbin-sti-subclass-from-attributes

Conflicts:
	activerecord/CHANGELOG.md

:nodoc: postgresql add_column

Add full set of MySQL CLI options to support SSL authentication when using db:structure dump and load

Add full set of MySQL CLI options to support SSL authentication when using db:structure dump and load

Add more detailed comment about _assign_attribute method [ci skip]

fix minor problems

Refactor abstract_mysql_adapter type_to_sql method

[ci skip] Don’t encourage `sudo gem install`

I think we are better off leaving `sudo` outside of the documented
way of installing gems (`activerecord`, `actionpack`, …).

We don’t want newbies to think that `sudo` is required or, even worse, than
they actually have to type `[sudo] gem install`.

In most scenarios, `sudo` is not needed to install gems, and people who do
need it, probably already know about it.

What do you think? 😁

This method has already been removed.

[ci skip] Fix `transaction` code example

Fix default value in guide [ci skip]

removing unused and already required require's

/cc @claudiob

[ci skip] Fix comment, since Rails 3.1 is out

custom test - Does not include EnvHelpers and the require is not needed
path generation test - require abstract_unit which has .  rails/all requires rails and corresponding

If your STI class looks like this:

```ruby
class Company < ActiveRecord::Base
  self.store_full_sti_class = false

  class GoodCo < Company
  end

  class BadCo < Company
  end
end
```

The expectation (which is valid) is that the `type` in the database is saved as
`GoodCo` or `BadCo`. However, another expectation should be that setting `type`
to `GoodCo` would correctly instantiate the object as a `Company::GoodCo`. That
second expectation is what this should fix.

[ci skip] Stop explaining finders for Rails 3

Stop skipping a test that now works on Rubinius

The test was skipped because of an issue that, in the meantime,
has been fixed: https://github.com/rubinius/rubinius/issues/3328.

Using the latest Rubinius (the one currently on Travis CI), this
is the result:

```sh
$ ruby --version
rubinius 2.5.3 (2.1.0 2482b093 2015-05-10 3.5.1 JI) [x86_64-darwin14.3.0]
```

**Before this PR**

```sh
$ ruby -Itest test/cases/attribute_assignment_test.rb
Run options: --seed 58569

.....S...

Finished in 0.048278s, 186.4203 runs/s, 269.2738 assertions/s.

9 runs, 13 assertions, 0 failures, 0 errors, 1 skips

You have skipped tests. Run with --verbose for details.
```

**After this PR**
$ ruby -Itest test/cases/attribute_assignment_test.rb
Run options: --seed 35720

.........

Finished in 0.029441s, 305.6961 runs/s, 475.5273 assertions/s.

9 runs, 14 assertions, 0 failures, 0 errors, 0 skips
```

Now that master points at Rails 5, we might not need to explain how
things used to work in Rails 3. Or we might… up to you 😁

[ci skip] Improve phrasing on #explain pretty printing.

[ci skip] Fix comment of `ActiveRecord::Associations#association_inst…

not needed require's

[ci skip] Fix purpose of `assert_kind_of`

- as core_ext is not used and test pass locally
- mail is already required in abstract_unit