Merge branch 'v9.0' of github.com:mongodb/docs-mongoid into v9.0

Author: rustagir

source/whats-new.txt

@@ -192,6 +192,8 @@ section of the Callbacks guide.
 Index Verification Configuration
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+.. versionadded:: 9.0.7
+
 You can use the ``Mongoid.allow_duplicate_index_declarations``
 configuration option to send index verification to
 the server. If a duplicate index is declared, the server raises an