Updating readme for DOCKER_SOCKET

Author: mohsenasm

README.md

@@ -14,7 +14,7 @@ It also shows the CPU/Memory/Disk usage of your swarm node and containers.
 
 ## Usage
 
-The dashboard needs to be deployed on one of the swarm managers.
+The dashboard can be deployed on one of the swarm managers.
 You can configure it with the following Docker compose file:
 
 ```yml
@@ -68,6 +68,8 @@ $ docker stack deploy -c compose.yml sd
 
 Note that the usage of `node-exporter` and `cadvisor` are optional, to fetch node CPU/Memory/Disk usage and containers' CPU/Memory usage respectively. If you don't specify `NODE_EXPORTER_SERVICE_NAME_REGEX` and `CADVISOR_SERVICE_NAME_REGEX` envs, the default is not using this feature, because of backward compatibility.
 
+If you prefer to deploy the dashboard on the worker nodes instead of the manager nodes (without the constraint `node.role == manager`), you can use the `DOCKER_SOCKET` configuration. Please check the following sections for more details.
+
 ## Advance Usage
 
 List of environment variables for more customization: