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? 😁

[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

[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

Refactor railties console and dbconsole commands

fix minor convention problems

correct error text message in engines.md [ci skip]

promote :except option instead of :only for before action docs [ci skip]

This moves `TemplateAssertions` out of the `test_case.rb` file and into
it's own `template_assertions` file. It still inherits from
`ActionController`.`

This is in preparation for combining the code for Integration tests and
Controller tests. This will need to be it's own file to be added to the
`requires` for Integration tests. This does not currently change ANY
behavior, just moving it for access later on.

`assert_emails` in block form use the given number as expected value

minor rdoc syntax fix [ci skip]

docs: syncing with the code, adding aj [ci skip]

change GeneratedFeatureMethods to GeneratedAssociationMethods in docs

the module name was changed in 8e814a0a

Provide provider_job_id to qu adapter.

as/core_ext require's not used

Better formatted documents [ci skip]