Adding user-service

Author: sivaprasadreddy

docs/index.md

@@ -21,6 +21,7 @@ $ git clone https://github.com/feature-tracker/docker-infra.git
 $ git clone https://github.com/feature-tracker/api-gateway.git
 $ git clone https://github.com/feature-tracker/feature-service.git
 $ git clone https://github.com/feature-tracker/notification-service.git
+$ git clone https://github.com/feature-tracker/user-service.git
 $ git clone https://github.com/feature-tracker/ft-webapp.git
 ```