Broadleaf Commerce Discussion Forums

I would like to sort and filter products based on average rating, but am not sure what would be the best way to achieve this.

I can extend the Product entity and retrieve the average rating via the blRatingService bean, now I guess I will need to add a new field in BLC_FIELD table in order for Solr to index it.
What would I put in the ENTITY_TYPE column?
Will I need to modify also the UI code?

Thanks for pointing me in the right direction