curl -X PUT https://app.trypost.it/api/signatures/e5f6a7b8-c9d0-1e2f-3a4b-5c6d7e8f9a0b \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Tech & AI",
    "content": "#tech #ai #machinelearning #startup"
  }'

{
  "id": "e5f6a7b8-c9d0-1e2f-3a4b-5c6d7e8f9a0b",
  "name": "Tech & AI",
  "content": "#tech #ai #machinelearning #startup",
  "created_at": "2025-01-10 08:00:00",
  "updated_at": "2025-01-10 09:00:00"
}