Setting Mongoid::Configuration.ignore_type_attribute=true will cause Mongoid to ignore the _type
attribute on queries where normal inheritance rules would apply that criteria, and will also ignore _type when marshaling objects from the database (preferring to use the calling class instead)

This fixes a situation I encountered wherein I was versioning document models by incrementing the module namespace they were a part of, but I wanted my existing documents to continue being fetched/queried by the new V2 document model.