Add links for latency based and geolocation based routing (donnemartin#319)

Author: varshavjm

README.md

@@ -601,8 +601,8 @@ Services such as [CloudFlare](https://www.cloudflare.com/dns/) and [Route 53](ht
  * Prevent traffic from going to servers under maintenance
  * Balance between varying cluster sizes
  * A/B testing
-* Latency-based
-* Geolocation-based
+* [Latency-based](https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html#routing-policy-latency)
+* [Geolocation-based](https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/routing-policy.html#routing-policy-geo)
 
 ### Disadvantage(s): DNS