API is missing 'periods' time_control_field for byoyomi in example

[dustyd]

Couldn’t figure out why I was getting an error trying to make a game with byoyomi time settings, turns out the API is missing the ‘periods’ field here

http://docs.ogs.apiary.io/#reference/challenges/challenges-list/create-a-new-open-challenge

Right now it reads:

"time_control_parameters": {
  "time_control": "byoyomi",
  "main_time": {int},
  "period_time": {int}
}

And it should be:

"time_control_parameters": {
  "time_control": "byoyomi",
  "main_time": {int},
  "period_time": {int},
  "periods": {int}, # ADDED THIS LINE
}