Add Gateio (#2802)

README.md

@@ -375,6 +375,7 @@ API | Description | Auth | HTTPS | CORS |
 | [CryptoTradingAPI](https://www.cryptotradingapi.io/) | Crypto Prices & Technical Indicators | `apiKey` | Yes | Unknown |
 | [Ethplorer](https://github.com/EverexIO/Ethplorer/wiki/Ethplorer-API) | Ethereum tokens, balances, addresses, history of transactions, contracts, and custom structures | `apiKey` | Yes | Unknown |
 | [FTX](https://docs.ftx.com/) | Complete REST, websocket, and FTX APIs to suit your algorithmic trading needs | `apiKey` | Yes | Yes |
+| [Gateio](https://www.gate.io/api2) | API provides spot, margin and futures trading operations | `apiKey` | Yes | Unknown |
 | [Gemini](https://docs.gemini.com/rest-api/) | Cryptocurrencies Exchange | No | Yes | Unknown |
 | [Indodax](https://github.com/btcid/indodax-official-api-docs) | Trade your Bitcoin and other assets with rupiah | `apiKey` | Yes | Unknown |
 | [INFURA Ethereum](https://infura.io/product/ethereum) | Interaction with the Ethereum mainnet and several testnets | `apiKey` | Yes | Yes |