Remove tabs, use spaces :scissors:

[ci skip]
Fix images in getting started guide.

We changed the error style, so they're all wrong. Now they're right.
:smile:
Getting Started Guide: strong_parameters

Stuff didn't work because of strong_parameters. Now the right calls are
in place.
fixing link to validations guide in getting started guide
Re-do Getting Started application with Rails 4.

The sample application with the Getting Started Guide was very out of
date. I've re-done it on edge (as of 51b9def5bf108fb566e) so it should
be good to go with Rails 4. It's also in synch with what the guide
actually says.
Remove unnecessary require

`require 'rubygems'` is already required in Ruby 1.9 or later.
Merge pull request #9026 from tricknotes/remove-unnecessary-require

Remove unnecessary require
avoid creating an object in every call

This was a suggestion of @carlosantoniodasilva, thanks!
Revert "updating i18n guide with locale config location."

This reverts commit 46902908910c041e268429d674bbe084399cc664.
Revert "Set the default timezone after the initialization since the configuration"

This reverts commit 39374aa925a7d670b039c0c0c9aa9f4aef19466b.
Revert "Merge pull request #7873 from steveklabnik/update_initializer"

This reverts commit 43e14f8ff203c21646f733d35bdde4e68da70a3b, reversing
changes made to bb17a0f085aba40a1952612f6c98b2a5804a1152.

Conflicts:
	railties/lib/rails/generators/rails/app/templates/config/application.rb
	railties/lib/rails/generators/rails/app/templates/config/initializers/locale.rb

Reason: setting the Time.zone in an after_initialize block can become a
problem for people upgrading, since it's not going to be available when
config/initializers run, and people might be relying on it.

An example that I noticed was with the Chronic gem, for date/time parsing.
It requires us to configure the time class to be Time.zone, and doing
that in an initializer no longer worked with these changes, so reverting
is the safer path for now.
Only check for unpermmited parameters if
action_on_unpermitted_parameters is present
Lets kepp using Ruby 1.9 syntax
Merge pull request #9027 from carlosantoniodasilva/revert-locale

Revert locale
Add failing test case for #8460

Add a test case to ensure that fractional second updates are detected.
Revert "Round usec when writing timestamp attribute."

This reverts commit e9d2ad395ec2ef929d74752f3d71c80674044fbe.

Closes #8460

Conflicts:
	activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
	activerecord/test/cases/dirty_test.rb
Less strict activerecord-deprecated_finders version
Added a test that shows that a HEAD request does not normally pass CSRF protection
Remove old asset tags API from docs, reflecting changes from #7900
Merge pull request #9031 from virusman/doc-no-asset-concat

Remove old asset tags API from docs