5.2.1
This patch level release has the following changes:
- Add support for matching the index of an array (@loganyu)
- MONGOID-4428 Ensure that a BSON::Regexp::Raw object is serialized to a BSON regex when querying a field with type String. Also allow a BSON::Regexp::Raw object to be compiled to a native Ruby Regexp when querying in-memory documents. Please ensure that all uses of Ruby's Regexp class refer to it with the explicit syntax:
::Regexp.