[spree-user] Extending spree search

Hi all,

I'm currently using Spree 1.2 with Ruby 1.9.3.

I have an additional field called 'tags' that I would like to add to a
product. I'm just wondering how I can extend the product search so that it
looks within this field for more keywords? Ideally I only want one field
that looks within the product title, description and 'tags' columns. I
can't find a search method within the product model to override?

Thanks in advance,

Ryan