gistfile1.txt

results = []
partners = []
36.downto(0) do |number|
	date = Time.now - number.months
	artworks = Artwork.where(:created_at.gte => date, :created_at.lt => date + 1.month)
	partners << artworks.map(&:partner_id)
	partners = partners.compact.uniq
	results << {"#{date.strftime}" => partners.size}
end