curl --request POST \
  --url https://api.brewit.ai/v1/auth/signin_external \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '{
  "external_id": "<string>",
  "ttl_seconds": 123,
  "display_name": "<string>",
  "email": "<string>",
  "picture": "<string>"
}'

{
  "token": "<string>",
  "expire": "<string>",
  "external_user_id": "<string>"
}