Prepped 5.0.2 release
Merge branch 'master' into 5.0-stable
Look in base table before looking in slug table for slugged model
Add failed tests for slug regeneration
Fix relation generation for new record
Add tests for slug regeneration in non scoped record
#dup with unslugged model causes undefined method error

In lib/friendly_id/base.rb:252:

```
    def dup
      super.tap { |duplicate| duplicate.slug = nil }
    end
```

However, suppose we have a User with just `friendly_id :login` - no extra slug. #slug= is not defined, and therefore some_user.dup fails.

My patch just makes the dup check if slug= is defined before using it.
Merge pull request #513 from PikachuEXE/fix/scoped-slug-regeneration

Fix/scoped slug regeneration
Fix typo in Initializer comments
Merge pull request #519 from 1ndivisible/comments-fix

Fix typo in Initializer comments

[ci skip]
A few readability improvements.
Merge pull request #520 from ugisozols/readability

A few readability improvements.

[ci skip]
Merge pull request #518 from saizai/patch-1

#dup with unslugged model causes undefined method error
Bump version to include #dup fix
Merge pull request #523 from saizai/patch-2

Bump version to include #dup fix
STI test failure

adding finders to both
cleaned up test

sub class of STI can't create records if parent
does not extend friendly id
Ensure finder methods are included in STI classes

Without this change, STI classes skipped adding the finders because
FriendyIdConfig#uses? would return true for FriendlyId::Finders when the
parent class had this module loaded, so the module loading would always
be skipped in the child module.

However, since FriendId::Finders.setup is always invoked when adding a
FriendlyId addon, the module will now get added to child classes.

See #516
Fix slug creation in STI classes

Previously, if the child class had the finder modules loaded but the
parent class did not, then slugs could not be created because the slug
generator assumed friendly finders were available, but were not because
the scope is uses comes from the super class rather than the child
class.

The child class scope is not used in order to maintain slug uniqueness
across child classes.

See #516
Extend FriendlyId in STI superclass.
Spelling fix