Grant a list of reward

Example request

{
  "elements": [
    {
      "reward_id": "REWARD1",
      "card_code": "44010000002",
      "quantity": 2,
      "reason_msg": "Catching up summer's free cake offer.",
      "grant_date": "2018-01-12 15:00:00",
      "burned_date": "2018-01-12 15:00:00",
      "validity_start": "2018-01-12 15:00:00",
      "validity_end": "2019-01-12 15:00:00",
      "store_id": "store01",
      "attribution_ids": [
        "reward_attribution_id_1",
        "reward_attribution_id_2"
      ]
    }
  ]
}