This option was removed from master.

[ci skip]

[ci skip]

Update configuration docs for assets.enabled, as it's set true by default in the configuration and doesn't appear in the config files anymore.

Same rationale as previous revert.

This reverts commit 887225e6.

It is not in the contract that flags have to be singletons,
the use of regular font indicates that.

This reverts commit 80036f9a.

/cc @fxn

We discussed that the auto explain feature is rarely used.
This PR removes only the automatic explain. You can still display
the explain output for any given relation using `ActiveRecord::Relation#explain`.

As a side-effect this should also fix the connection problem during
asset compilation (#9385). The auto explain initializer in the `ActiveRecord::Railtie`
forced a connection.

Capitalization in the title of the section, enumerates the environments
in the usual order, adds a paragraph, and tries to use less "you"s.

Replaced documentation for config.action_controller.raise_on_unpermitted_parameters with documentation for config.action_controller.action_on_unpermitted_params.

Proxy servers add X-Forwarded-For headers, resulting in a list of IPs. We
remove trusted IP values, and then take the last given value, assuming that
it is the most likely to be the correct, unfaked value. See [1] for a very
thorough discussion of why that is the best option we have at the moment.

[1]: http://blog.gingerlime.com/2012/rails-ip-spoofing-vulnerabilities-and-protection/

Fixes #7979

This can be done using the class attribute cache_timestamp_format

Conflicts:
	railties/guides/source/configuring.textile

There's no reason for guides to reference old behaviors. They should
be current as of the versions of Rails that they ship with, and including
older information just clutters thing.

I discussed this change with @fxn and he agrees.

We have three or four different introduction sentences to the guides.
After this commit, we use the same one everywhere.

Talked with @fxn about this. Bullet points should have periods at the ends.

They was extracted from a plugin.

See https://github.com/rails/rails-observers

[Rafael Mendonça França + Steve Klabnik]