consul: add source code link

README.md

@@ -631,7 +631,7 @@ _Related: [Databases](#databases), [Monitoring](#monitoring)_
 
 **[`^        back to top        ^`](#awesome-sysadmin)**
 
-- [Consul](https://www.consul.io/) - Consul is a tool for service discovery, monitoring and configuration.
+- [Consul](https://www.consul.io/) - Consul is a tool for service discovery, monitoring and configuration. ([Source Code](https://github.com/hashicorp/consul))
 - [Doozerd](https://github.com/ha/doozerd) - Doozer is a highly-available, completely consistent store for small amounts of extremely important data.
 - [etcd](https://github.com/coreos/etcd) - distributed K/V-Store, authenticating via SSL PKI and a REST HTTP Api for shared configuration and service discovery.
 - [ZooKeeper](http://zookeeper.apache.org/) - ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services.