Grab unique vintages for accounts stocks.

stock.rb

def stocked_styles
  joins("INNER JOIN wine_instances wi ON wi.id = stocks.wine_instance_id INNER JOIN wines w ON w.id = wi.wine_id INNER JOIN styles s ON s.id = w.style_id").select("DISTINCT(s.name) AS style_name").order("style_name").map { |s| s.style_name }
end