Update readme to show usage of Request-Id middleware (#47)

- Add help to show steps to include request-id middleware

README.md

@@ -131,6 +131,36 @@ func (s *MyService) MyMethod(ctx context.Context, req *MyMethodRequest) (*MyMeth
 }
 ```
 
+##### Request-Id
+
+We support cases where each request need to be assigned with its own request_id, so when the request goes from one service to another it can be easily traced in logs.
+
+Request-Id interceptor will extract Request-Id from incoming metadata and update context with the same.
+
+##### How can I add support for Request-Id to track my requests?
+
+You can enable support of Request-Id middleware in your gRPC-Server by adding
+
+```golang
+import (
+  ...
+  ...
+  "github.com/infobloxopen/atlas-app-toolkit/requestid"
+)
+func main() {
+    server := grpc.NewServer(
+      grpc.UnaryInterceptor(
+        grpc_middleware.ChainUnaryServer(  // middleware chain
+          ...
+          requestid.UnaryServerInterceptor(),  // Request-Id middleware
+          ...
+          ),
+        ),
+      )
+    ...
+}
+```
+
 #### Validation
 We recommend to use [this validation plugin](https://github.com/lyft/protoc-gen-validate) to generate
 `Validate` method for your gRPC requests.