This reverts commit 1c02b988.

This reverts commit 93b1ca8b.

Thanks to @jeremy to teach me this one.

This reverts commit 4e9f53f9, reversing
changes made to 6b802cdb.

Revert "Don't use tap in this case."

This reverts commit 454d820b.

Reason: Is not a good idea to add options to this method since we can do
the same thing using method composition.

    Person.validators_on(:name).select { |v| v.kind == :presence }

Also it avoids to change the method again to add more options.

The use of tap in this case is very confusing since we are mutating the
return value inside the block

This will filter out the validators on a particular attribute based on
its kind.

This commit allows a user to do something like:
    before_validation :do_stuff, :on => [ :create, :update ]
    after_validation :do_more, :on => [ :create, :update ]

attr_accessible and attr_protected raise an exception pointing to use plugin or new protection model

Change AMo::ForbiddenAttributesProtection tests to use a subclass of Hash instead of monkey patch permitted? method in regular hashes

This will be moved out to protected_attributes gem

Due to a change in builder, nil values and empty strings now generates
closed tags, so instead of this:

    <pseudonyms nil=\"true\"></pseudonyms>

It generates this:

    <pseudonyms nil=\"true\"/>

Document this change in Rails so that people can track it down easily if
necessary.

Changes in old branches needed to be manually synched in CHANGELOGs of newer ones.
This has proven to be brittle, sometimes one just forgets this manual step.
With this commit we switch to CHANGELOGs per branch. When a new major version is
cut from master, the CHANGELOGs in master start being blank.

A link to the CHANGELOG of the previous branch allows anyone interested to
follow the history.

The new option allows any Ruby namespace to be registered and set
up for eager load. We are effectively exposing the structure existing
in Rails since v3.0 for all developers in order to make their applications
thread-safe and CoW friendly.

- Enable propagation of :skip_types, :dasherize and :camelize on included models by default
- Adding the option to override this propagation on a per-include basis (:include => { :model => { :dasherize => false } }
- Enough tests to prove it works
- Updated activemodel CHANGELOG.md

Squashed my commits

Under a "private" call, class methods are not real private methods,
they're public just like any other method.

Make model_name_from_record_or_class a private class method, and nodoc it.