v5.0.2

This release has a number of fixes for bugs in the backlog, community contributions, and tests added to show some issues no longer exist.

• MONGOID-4113 Spec added, no longer an issue
• MONGOID-3659 Spec added, no longer an issue
• MONGOID-3697 Hash.mongoize returns a new hash
• MONGOID-3782 Spec added, no longer an issue
• MONGOID-3709 Support nested polymorphic association assignment
• RUBY-1060 Set mongo logger to mongoid logger
• MONGOID-4137 Fix no method error for 'substitute'
• MONGOID-4128 Don't use $in if 1 subclass in criteria
• MONGOID-3919 Spec added, no longer an issue
• MONGOID-4181 Spec added, no longer an issue
• MONGOID-3808 Don't update db if validation fails
• MONGOID-2984 Don't update db if validation fails
• Remove deprecations form 5.0
• MONGOID-4189 Use index name for comparing text indexes
• RUBY-1072 Add limit of 1 to Model#first and Model#last to avoid leaving cursors open
• MONGOID-3417 Spec added, no longer an issue
• MONGOID-3407 Support using dot notation for attribute assignment (@sivagollapalli)
• Support partial indexes (@amw)