Add dYdX (#2843)

README.md

@@ -376,6 +376,7 @@ API | Description | Auth | HTTPS | CORS |
 | [CryptoMarket](https://developers.cryptomkt.com) | Cryptocurrencies Trading platform | `apiKey` | Yes | Yes |
 | [Cryptonator](https://www.cryptonator.com/api/) | Cryptocurrencies Exchange Rates | No | Yes | Unknown |
 | [CryptoTradingAPI](https://www.cryptotradingapi.io/) | Crypto Prices & Technical Indicators | `apiKey` | Yes | Unknown |
+| [dYdX](https://docs.dydx.exchange/) | Decentralized cryptocurrency exchange | `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 |