Add Rel.ink under URL shorteners category (#984)

README.md

@@ -828,6 +828,7 @@ API | Description | Auth | HTTPS | CORS |
 | [CleanURI](https://cleanuri.com/docs) | URL shortener service | `No` | Yes | Yes |
 | [ClickMeter](https://support.clickmeter.com/hc/en-us/categories/201474986) | Monitor, compare and optimize your marketing links | `apiKey` | Yes | Unknown |
 | [Rebrandly](https://developers.rebrandly.com/v1/docs) | Custom URL shortener for sharing branded links | `apiKey` | Yes | Unknown |
+| [Relink](https://rel.ink) | Free and secure URL shortener  | No | Yes | Yes |
 
 ### Vehicle
 API | Description | Auth | HTTPS | CORS |