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

I think that these signs are probably mistake.

to avoid unnecessary reg ex parsing and code
<http://httpd.apache.org/docs/2.2/mod/core.html#location
(recommended by @jja). - @erikj

[ci skip]

[ci skip]

This reverts commit dd319600.

This reverts commit 814c9875.

Adds documentation for:
- Aggregate cache keys,
- using an ActiveRecord model as cache key and
- Russian Doll Caching.

* 1.9 hash syntax
* proper formatting around one line blocks
* do-end for multiline blocks

Conflicts:
	guides/source/getting_started.md

view_cache_dependency API

A declarative API for specifying dependencies that affect template
cache digest computation. In your controller, specify any of said
dependencies:

  view_cache_dependency { "phone" if using_phone? }

When the block is evaluated, the resulting value is included in the
cache digest calculation, allowing you to generate different digests
for effectively the same template. (Mostly useful if you're mucking
with template load paths.)

set 'alt' attribute for image_submit_tag

Revert "unpermitted params" exception -- it's just not going to work. See the discussion on https://github.com/rails/strong_parameters/pull/75.

It includes security bug fixes and changes the initialization of
Rack::File to accept a hash, otherwise generating warnings.

See 295806e1 for the warnings fix.

Eliminate Rack::File headers deprecation warning

See http://intertwingly.net/projects/AWDwR4/checkdepot/section-6.1.html
rake test produces:
   "Rack::File headers parameter replaces cache_control after Rack 1.5."

Despite what the message says, it appears that the hearders parameter change
will be effective as of Rack 1.5:

https://github.com/rack/rack/blob/rack-1.4/lib/rack/file.rb#L24
https://github.com/rack/rack/blob/master/lib/rack/file.rb#L24

Previously rendering a partial without giving :object or :collection
would generate a local variable with the partial name by default.

This was noticed due to warnings in Ruby 2.0 of not used variables,
which turned out to be the generation of not used variables inside
partials that do not contain objects related to them.

Some tests were raising the following error:

    Could not log "sql.active_record" event. NoMethodError: undefined method
    `type' for nil:NilClass`

Due to the way binds were being logged, the column info was considered
always present, but that is not true for some of the tests listed in the
issue.

Closes #8806.