Create Favorite Crypto

/v1/favorite-cryptos

curl -X POST http://localhost:8080/v1/favorite-cryptos \
  -H "Content-Type: application/json" \
  -d '{
    "email": "user@example.com",
    "ticker": "BTCUSDT"
  }'

{
  "id": "507f1f77bcf86cd799439011",
  "email": "user@example.com",
  "ticker": "BTCUSDT",
  "timestamp": 1234567890000
}