orders:
    user001:    // this is user 1
        11168128:
            name: "order 1"
            status: "pending"
        11168129:
            name: "order 2"
            status: "canceled"
    user002:    // this is user 2
        11168130:
            name: "order 3"
            status: "pending"
    user003:    // this is user 3
        11168131:
            name: "order 4"
            status: "pending"
        11168132:
            name: "order 5"
            status: "canceled"

this.orders = this.db.list(`orders`)
  .snapshotChanges().map(changes => {
       return changes.map(c => ({ key: c.payload.key, ...c.payload.val() }));
});