Added missing link

README.md

@@ -35,7 +35,7 @@ public function resolveIpLocation(string $ipAddress): Model\Location;
 These are the strategies provided implementing this interface:
 
 * `GeoLite2LocationResolver`: It makes use of a [GeoLite2](https://dev.maxmind.com/geoip/geoip2/geolite2/) database to resolve IP address locations.
-* `IpApiLocationResolver`: It calls [IP API]() in order to resolve IP address locations (this API is a little bit fragile and easily ends up blocking callers).
+* `IpApiLocationResolver`: It calls [IP API](http://ip-api.com) in order to resolve IP address locations (this API is a little bit fragile and easily ends up blocking callers).
 * `EmptyIpLocationResolver`: This one is a dummy resolver which always returns an empty location as if it was not capable of resolving the address location.
 * `CainIpLocationResolver`: It wraps a list of IP resolvers and calls them sequentially until one of them is capable of resolving the address location.