curl --request POST \
  --url https://api.railmail.app/api/v1/segments \
  --header 'Content-Type: application/json' \
  --header 'X-API-Key: <api-key>' \
  --data '
{
  "name": "<string>",
  "description": "<string>",
  "rules": "<string>"
}
'

{
  "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "segmentKey": "<string>",
  "name": "<string>",
  "description": "<string>",
  "type": "<string>",
  "rules": "<string>",
  "status": "<string>",
  "memberCount": 123,
  "createdAt": "2023-11-07T05:31:56Z",
  "updatedAt": "2023-11-07T05:31:56Z"
}