Schéma de purchases

{
      "customerId": String,
      "lineItems": [
        {
          "count": Number,
          "product": String
        } 
      ],
      "purchaseId": String,
      "purchasedAt": String,
      "type": String
    }

Exemple d'un objet :

{
      "customerId": "customer515",
      "lineItems": [
        {
          "count": 3,
          "product": "product701"
        },
        {
          "count": 4,
          "product": "product85"
        }
      ],
      "purchaseId": "purchase0",
      "purchasedAt": "2014-04-06T15:52:32Z",
      "type": "purchase"
    }