Add CoinDesk API

README.md

@@ -202,6 +202,7 @@ API | Description | Auth | HTTPS | Link |
 API | Description | Auth | HTTPS | Link |
 |---|---|---|---|---|
 | Barchart OnDemand | Stock, Futures, and Forex Market Data | `apiKey` | Yes | [Go!](https://www.barchartondemand.com/free) |
+| CoinDesk | Bitcoin Price Index | No | No | [Go!](http://www.coindesk.com/api/) |
 | Consumer Financial Protection Bureau | Financial services consumer complains data | `apiKey` | Yes | [Go!](https://data.consumerfinance.gov/resource/jhzv-w97w.json) |
 
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