Add live current round data endpoint for React

[geerlingguy]

See title.

[geerlingguy]

 13:30:01 ~ 
$ curl http://127.0.0.1:5000/live/round
[
  {
    "close_time": null,
    "is_accepting_votes": 1,
    "is_allowing_multiple_votes": 1,
    "is_current": 1,
    "round_id": 8,
    "start_time": null,
    "value_0": "Chicken",
    "value_1": "Steak",
    "value_2": "Oatmeal"
  }
]