Add IPInfoDB API (#891)

* Update README.md

* Update README.md

README.md

@@ -423,6 +423,7 @@ API | Description | Auth | HTTPS | CORS |
 | [IP Sidekick](https://ipsidekick.com) | Geolocation API that returns extra information about an IP address | `apiKey` | Yes | Unknown |
 | [IP Vigilante](https://www.ipvigilante.com/) | Free IP Geolocation API | No | Yes | Unknown |
 | [IPGeolocationAPI.com](https://ipgeolocationapi.com/) | Locate your visitors by IP with country details | No | Yes | Yes |
+| [IPInfoDB](https://ipinfodb.com/api) | Free Geolocation tools and APIs for country, region, city and time zone lookup by IP address | `apiKey` | Yes | Unknown |
 | [ipstack](https://ipstack.com/) | Locate and identify website visitors by IP address | `apiKey` | Yes | Unknown |
 | [LocationIQ](https://locationiq.org/docs/) | Provides forward/reverse geocoding and batch geocoding | `apiKey` | Yes | Yes |
 | [Mapbox](https://www.mapbox.com/developers/) | Create/customize beautiful digital maps | `apiKey` | Yes | Unknown |