add changelog entry for #11945

Allows you to change your configuration for calls to
`table_name_prefix`, `table_name_suffix`, and `pluralize_table_names`.
The default configuration is still ActiveRecord::Base, but you are now
able to change the configuration easily.

Closes #11899.

Also, +ActiveRecord::Migrator.proper_table_name+ should actually have a
deprecation horizon of Rails 4.2 (not 4.1).

Also, constantizing the default_fixture_model_name when it gets loaded
in from the file. Later, when the class_name is passed to a new
FixtureSet, a deprecation warning will occur if the class_name is a
string.

The options will specify the prefix and the suffix. Also, I'm moving the
method to be an instance method on the +Migration+ instance. This makes more
sense than being a class method on the +Migrator+ class because the only
place that uses it is on a +Migration+ instance (in a method_missing
hook). The logic for the Migrator shouldn't be doing any work to
calculate the table name, it should be the Migration itself.

Also made some small indentation fixes.

Caches the patterns of ActiveRecord::DynamicMatchers in a class instance
variable.

This fixes a regression. The documentation said in its introduction
paragraph that the method returns truthy/falsy, but then below it
was said that if there were no arguments you'd get `true` or `false`.
Also when the argument is exactly `false` a singleton is documented
to be returned.

The method was not returning the singletons so it didn't conform to
those special cases.

The best solution here seems to be to just return singletons in all
cases. This solution is backwards compatible. Also, the contract
has been revised because it has no sense that the predicate varies
that way depending on the input. I bet the previous contract was just
an accident, not something mixed on purpose.

Conflicts:
	activerecord/lib/active_record/relation/finder_methods.rb
	activerecord/test/cases/finder_test.rb

This reverts commit 70d6e16f, reversing
changes made to ea4db3bc.

Seems to be a code merge done by mistake.

SQL doesn't have a string type, and interpreting 'string' as text is
contrary to at least SQLite3's behavior:

"Note that a declared type of 'STRING' has an affinity of NUMERIC, not TEXT."
http://www.sqlite.org/datatype3.html

Currently, ActiveRecord models with multiple words cannot have their
inverse associations detected automatically.

In order that set attribute should not be bang method

Restore the use of `#add_to_target` for nested attribute updates on existing records, and don't bother updating the association if the update is going to be rejected anyway.

This requires adding a `skip_callbacks` argument to `#add_to_target`
so that we don't call the callbacks multiple times in this case,
which is functionally an application of existing association data,
rather than an addition of a new record to the association.

Issue #1: :before_add callback is called when nested attributes assignment assigns to existing record if the association is not yet loaded
Issue #2: Nested Attributes assignment does not affect the record in the association target when callback triggers loading of the association

If you're using an in-memory database for the test database,
reconnecting will lose all information that schema:load did for us.

If 'enable_extension' is used in a migration's 'change' method, use
'disable_extension' on down migration (and vice-versa).

This change was breaking the Railties tests. See
https://travis-ci.org/rails/rails/jobs/9865969

The deprecation message was removed on 50cbc03d but the code was not.

If the `db/` directory is not present on a remote machine it will blow up in unexpected ways with error messages that do not indicate there is a missing directory:

```
SQLite3::CantOpenException: unable to open database file
```

This PR checks to see if a directory exists for the sqlite3 file and if not creates it for you.

This PR is an alternative to #11692 as suggested by @josevalim

`result_metadata` returns a new object each time it is called, so calling `result_metadata.free` is essentially a noop.  Instead call `free` directly on the metadata when we're done with it.