This is done because concerns of respective steps can be separated,
which in turns leads to easier walkthrough and verbosity. Also
stretching a function to large horizontal bounds doesn't looks good.

Allow `rails new . --master` to point to master branch

Properly close a tag to avoid errors with some ruby versions

Co-Authored-By: NRafael França <rafael@franca.dev>

Here we want end of string, no optional newlines are to
be expected, so \z is more concise.

Deduplicate Module#module_parent_name cache

[guides] Update missing translation example

Fixed Active Storage Overview guide containing XSS vulnerability

It raises an error if the ruby version is 2.5.0

Refactor invert predicate

Instead of doing a case statement here we can have each of the objects
respond to `invert`. This means that when adding new objects we don't
need to increase this case statement, it's more object oriented, and
let's be fair, it looks better too.

Aaron and I stumbled upon this while working on some performance
work in Arel.

I removed `random_object` from the invert test because we don't support
random objects. If you pass a random object to Arel, it should raise,
not be inverted.
Co-authored-by: NAaron Patterson <aaron.patterson@gmail.com>

Add support for que name to Que adapter.

Co-authored-by: NBrad Nauta <bradnauta@gmail.com>

Currently the `rails new` generator supports options `—dev` and `—edge`.

`—dev` points to one’s local rails setup and `--edge` points to the latest stable Rails branch.

However, in the Rails community we often think of the ‘edge’ as the latest merged master. We can see as much in Shopify’s fantastic article showing how they point to the latest master version of Rails: https://engineering.shopify.com/blogs/engineering/living-on-the-edge-of-rails

I would originally have recommended changing ‘edge’ to point to master, as it has tripped me up on numerous occasions now.

However I would rather add the desired functionality then change the current edge functionality.

Therefore this PR adds the `—master` flag.

It is intended to do exactly as `edge` does, simply with the changethat it points to Rails’ master branch instead of latest stable (i.e. 6_0_stable)

Whenever developers see a new feature in Rails, such as the recently committed horizontal sharding (which prompted my PR), we would love to spin up a new Rails App to try out these new features.

This command would allow us to jump right in with no configuration and offer our testing of the features, even those of us who aren’t able to spend a lot of time on OSS support.

Fix AJ wrong deprecation message on `after_callbacks_if_terminated`:

- ### Problem

  In some cirumstances, the deprecation message to warn that AJ won't
  run `after_(enqueue/perform)` callbacks when the chain is halted
  by a `throw(:abort)` will be thrown even though no `throw(:abort)`
  was thrown.

  ```ruby
    run_callback(:foo) do
      ...
    end
  ```

  There is two possible way for the callback body to not be executed:

  1) `before` callback throw a `abort`
  2) `before` callback raises an error which is rescued by an
     around callback (See associated test in this commit for
     an example)

  When 2) happen we don't want to output a deprecation message,
  because what the message says isn't true and doesn't apply.

  ### Solution

  In order to differentiate between 1) and 2), I have added
  a `halted_callback_hook` which is called by ActiveSupport callback
  whenever the callback chain is halted.

- The `halted_callback_hook` method is called whenever the
  `terminator` halt the callback execution.
  Usually, this translate to when a `before` callback throw
  an `:abort`.

  <details>
    <summary> Example </summary>

    ```ruby
      class Foo
        include ActiveSupport::Callbacks

	define_callbacks :save
	set_callback(:save, :before) { throw(:abort) }

	def run
	  run_callbacks(:save) do
	    'hello'
	  end
	end

	def halted_callback_hook(filter)
	  # filter is the proc passed to `set_callback` above
	end
      end
    ```
  </details>

  ### Problem

  When a class has multiple callbacks, (i.e. `save`, `validate` ...),
  it's impossible to tell in the halted_callback_hook which type of
  callback halted the execution.
  This is useful to take different action based on the callback.

  <details>
    <summary> Use Case </summary>

    ```ruby
      class Foo
        include ActiveSupport::Callbacks

	define_callbacks :save
	define_callbacks :validate

	set_callback(:save, :before) { throw(:abort) }
	set_callback(:validate, :before) { throw(:abort) }

	def run
	  run_callbacks(:validate) do
	    ...
	  end

	  run_callbacks(:save) do
	    ...
	  end
	end

	def halted_callback_hook(filter)
	  Rails.logger.warn("Couldn't save the record, the ??? callback halted the execution")
	end
      end
    ```
  </details>

  ### Solution

  Allow `halted_callback_hook` to receive a second argument which is
  the name of the callback being run.

Simplify route score

Add activerecord/db/ to gitignore

The Rails Guides contain an example of how to raise for a missing
translation when `I18n.t` is called from anywhere, including
non-ActionView contexts. The example builds a custom exception handler
that catches and raises any instance of `I18n::MissingTranslationData`
and passes on any other exception to be handled by `I18n` as normally
happens.

Unfortunately, while `I18n::MissingTranslationData` is what eventually
should be raised for a missing translation, the initial exception the
handler sees is actually `I18n::MissingTranslation`, and
`MissingTranslationData` is the product of calling `#to_exception` on
that exception object. As a result, the example in the guides ends up
not raising for missing translations, silently resulting in the return
of the missing translation key.

This change updates the guides to with a working example, catching
`I18n::MissingTranslation` which results in a raise of
`I18n::MissingTranslationData` with the missing key.

After running `bundle exec rake test:sqlite3` and `bundle exec rake test:sqlite3_mem`
on my VM I noticed that it had created untracked files:

```bash
vagrant@ubuntu-bionic:/rails/activerecord$ git status
Untracked files:
  (use "git add <file>..." to include in what will be committed)
        db/
        file::memory:
```

To prevent them from being accidentally committed I put 'file::memory:' to
`activerecord/db/` folder and added the folder to .gitignore
Also, we could consider fixing this by removing `db/` folder in each test that
creates the folder.

It would be great if someone confirms that it happens not only on my VM.

Fixed typo classsic -> classic [ci skip]

Fix error in deprecation

[ci skip] Security guide: change raw HTML elements and signs to backquoted ones

When I implemented the deprecation for #38536 I left in the setter in
the initalizer. This meant that objects returned had both `@name` and
`@spec_name` set and objects looked like this:

```
<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fe0f7100c68
  @env_name="development",
  @name="primary",
  @spec_name="primary",
  @config={
    :adapter=>"mysql2",
    :database=>"recipes_app_development"
  }
>
```

Since we don't use the kwarg to create the hash config and we have the
reader for reading off the object or selecting from the configurations
objects list we can remove this so the object looks like:

```
<ActiveRecord::DatabaseConfigurations::HashConfig:0x00007fe0f7100c68
  @env_name="development",
  @name="primary",
  @config={
    :adapter=>"mysql2",
    :database=>"recipes_app_development"
  }
>
```

Testing Guides: Added section on Parallell Testing of Transactions

Based on https://github.com/rails/rails/issues/38578, it would be nice to have some information on transactions in test cases

Closes #37435.

ActionText is using ActionView in a way that ActionView doesn't have in
it's test suite.  This is just a regression test to hit that same use
case.

[ci skip] Documentation: Use yml extension for locale files example

The default extension we use for locale files is `.yml`. This patch
reflects this in the documentation example.

Dumps the schema or structure of a database when calling db:migrate:name