Add Twelve Data API (finance section)

README.md

@@ -348,6 +348,7 @@ API | Description | Auth | HTTPS | CORS |
 | [Plaid](https://plaid.com/) | Connect with users’ bank accounts and access transaction data | `apiKey` | Yes | Unknown |
 | [Razorpay IFSC](https://ifsc.razorpay.com/) | Indian Financial Systems Code (Bank Branch Codes) | No | Yes | Unknown |
 | [Tradier](https://developer.tradier.com) | US equity/option market data (delayed, intraday, historical) | `OAuth` | Yes | Yes |
+| [Twelve Data](https://twelvedata.com/) | Stock market data (real-time & historical) | `apiKey` | Yes | Unknown |
 | [YNAB](https://api.youneedabudget.com/) | Budgeting & Planning | `OAuth` | Yes | Yes |
 
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