Add 0x (#2762)

README.md

@@ -331,6 +331,7 @@ API | Description | Auth | HTTPS | CORS |
 ### Cryptocurrency
 API | Description | Auth | HTTPS | CORS |
 |---|---|---|---|---|
+| [0x](https://0x.org/api) | API for querying token and pool stats across various liquidity pools | No | Yes | Yes |
 | [1inch](https://docs.1inch.io/api/) | API for querying decentralize exchange | No | Yes | Unknown |
 | [apilayer coinlayer](https://coinlayer.com) | Real-time Crypto Currency Exchange Rates | `apiKey` | Yes | Unknown |
 | [Binance](https://github.com/binance/binance-spot-api-docs) | Exchange for Trading Cryptocurrencies based in China | `apiKey` | Yes | Unknown |