Also add around save to creating/updating callbacks order, and fix save
example with no validation

Use ActiveModel::Errors in inflection example docs as well.

Also fixes wrong information and link to locale file related to
Errors#full_messages in I18n guide.

The methods validate_on_create and validate_on_update are not available
anymore in Rails, this removes them from the guide and adds an example
on how to use validate with the :on option.

"will be used throughout all the views for posts." could suggest, that code's modification is somehow related to posts, while it's application-wide

This reverts commit ecac7c96.

Reason: Changelogs are not meant to be changed from docrails.

change AR default_timezone to :utc since it's the default for AR::Railtie

Replace regexp matching with a simple string manipulation.

Using regexp looks like overkill here and is also 2x slower.

             user     system      total        real
string   0.020000   0.000000   0.020000 (  0.016256)
regexp   0.030000   0.000000   0.030000 (  0.035360)

require "benchmark"

names = ("a".."z").map { |c| c + "a" * rand(5..10) + "=" * rand(0..1) }.map(&:to_sym)
puts names

n = 1000
Benchmark.bmbm do |x|
  x.report "string" do
    n.times do
      names.each do |name|
        string_name = name.to_s
        string_name.chomp!('=')
        string_name
      end
    end
  end

  x.report "regexp" do
    n.times do
      names.each do |name|
        name.to_s =~ /(.*)=$/
        $1
      end
    end
  end
end

Refactor NumberHelpers

From 2c667f69.

Thanks @pwnall for the heads-up.

Fix for log tailer when the log file doesn't exist.

Removed unused assigns from ActionView::Template::Error

No need to check html_safe? twice at number_to_percentage

This reverts commit be7d2248.