Restoring polymorphic has_one relationships errored because paranoia was
not correctly looking up the foreign_key.

Output from failing test -

ActiveRecord::StatementInvalid: SQLite3::SQLException: no such column: parent_model_id: SELECT  "polymorphic_models".* FROM "polymorphic_models" WHERE ("polymorphic_models"."deleted_at" IS NOT NULL) AND (parent_model_id)  ORDER BY "polymorphic_models"."id" ASC LIMIT 1

The test sets up a PolymorphicModel, which has_many parents. The
ParentModel then has a has_one relationship with PolymorphicModel. When
restoring, the foreign key is set as - `self.class.name.to_s.underscore_id`
which will be parent_model_id, instead of the :as option.

DEPRECATION WARNING: Currently, Active Record suppresses errors raised within `after_rollback`/`after_commit` callbacks and only print them to the logs. In the next version, these errors will no longer be suppressed. Instead, the errors will propagate normally just like in other Active Record callbacks.

apply the deprecation fix for ActiveRecord >= 4.2 only

DEPRECATION WARNING: You are passing an instance of ActiveRecord::Base to `find`. Please pass the id of the object by calling `.id`. (called from block in restore at /Users/sergey/ruby_projects/paranoia/lib/paranoia.rb:38)

Change-Id: Ib73e43a5adcb8bd9b5bbf5b7ca60f9865e5415e7

Regression from 6881e750

We need to be able to load our class definitions without having an
available database connection.

Change connect! to setup!, so that we can use connect! to give us an
empty DB with no tables.

Use ensure where appropriate to ensure that tests after that one can run
even if it fails.

This reverts commit 6881e750.

see https://github.com/radar/paranoia/issues/169

Use fetch for sentinel_value

Use DateTime for sentinel_value example

Use an epoch. rails convers '0' or 0 to nil for datetime fields

Add test for restore

Update readme

Move MYSQL note to bottom of readme

update destroyed? for sentinel value

This reverts commit 566b1cbd.

Conflicts:
	README.md
	test/paranoia_test.rb

Fixes #149

Fixes #148

Fixes #143

Fixes #138

Removed deprecated assert_nothing_raised from test.

when the model has_one use class_name or foreign_key, restore use
class_name or setting the foreign_key.

Fixes #117

  * Based on partial fix by @stupergenius
  * Handles nil case for hasOne associations

Fixes #119

Rails normally returns the model on successful destroy and false if any
callback fails.

Fixes #104

Fixes #95

As per #92

Fixes #91

Fixes #81
Fixes #84

Conflicts:
	lib/paranoia.rb

Update/save callbacks should not be called at all during a destroy call, as would happen with the code from that PR.

References: https://github.com/goncalossilva/acts_as_paranoid

Fixes #76

Fixes #72

Modelled on AR::Relation.destroy