compact key

gistfile1.txt

def get_loyalty(date_range, page_id)
    loyalty_users = {}
    date_range.each{|range|
      loyalty_users.merge!([range[:month], range[:year]] => find_loyaltys(range[:month], range[:year], page_id))
    }
    return loyalty_users
  end

this comes out like 

users_loyalty: {
[8, 2012]: [ ],
[9, 2012]: [ ],
[10, 2012]: [
{
_id: {
$oid: "509d2256844d8b1810000019"
},
name: "Baso car",
category: "Automobiles and parts",
id: "276256145729599",
month: 10,
year: 2012,
page_id: "58128939954"
},

i want it to be like 

users_loyalty: {
[82012]: [ ],
[92012]: [ ],
[102012]: [
{
_id: {
$oid: "509d2256844d8b1810000019"
},
name: "Baso car",
category: "Automobiles and parts",
id: "276256145729599",
month: 10,
year: 2012,
page_id: "58128939954"
},