Create background tracks

curl --request POST \
  --url https://api.beyondwords.io/v1/background_tracks \
  --header 'Content-Type: application/json' \
  --header 'X-Api-Key: <api-key>' \
  --data '{
  "project": {
    "id": 1
  },
  "name": "Test track 1",
  "media": {
    "url": "https://example.com/transcoded.mp3"
  }
}'

{
  "id": 1,
  "name": "Test track 1",
  "volume": 100,
  "created": "2023-01-01 00:00:00 UTC",
  "updated": "2023-01-01 00:00:05 UTC"
}