Create subscriber

Creates a subscriber record. Adds record to subscription list if specified otherwise adds to all contacts.

Example curl command:

curl -X POST \
https://api.paubox.com/v1/marketing/subscribers \
  -H 'authorization: Token token=<API_KEY>' \
  -H 'content-type: application/json' \
  -d '{
    "subscriber": {
        "email": "test@example.com",
        "first_name": "test",
        "last_name": "example"
    }
  }'