Update readme to add information on node-reporter

readme.md

@@ -49,6 +49,13 @@ You can also use a SSL certificate for API as described in [vidjil documentation
 On target server, you need to set up a metrics user if not already done. 
 See this [page](https://www.vidjil.org/doc/admin/#server-monitoring) for more information on how to do that.
 
+#### Node reporter
+
+Node reporter isa dedicated service to follow hardware of a server (CPU and memory usage, disk space, ...).
+It should be launch on each target and declared in prometheus as specified below.
+
+You can use for that dedicated `docker-compose-node.yml` file. 
+
 
 ## Launch services
 
@@ -59,7 +66,8 @@ docker-compose up -d
 ```
 
 Note that for the moment, no image is avaialbe for vidjil metrics.
-At first lauch, you should add `--build` at `docker compsoe up -d` to build metrics server image.
+At first lauch, you should launch `make build_metrics` to build metrics docker images that will be used. 
+Note that if you made some dev and want to build again this image, you can add `--build` at `docker compsoe up -d` to build metrics server image at launch.
 
 By default, only grafana server will be serve on port 3000.
 As metrics and prometheus don't allow to manage user and credential,