Is there a way to return monthname when you use group_by_month?

[acp15ak]

I am using:
PurchaseHistory.group_by_month(:purchase_date,"sum","quantity*price")
It returns the following output:
"2015-08-01 00:00:00 UTC"=>40.0
Is there a way to get monthname instead of the whole timestamp?

[rusgrafx]

Haven't tried dateslices yet, but in Groupdate it could be done with 'format' like that:

.group_by_month(:purchase_date,"sum","quantity*price", format: '%b')