Add chapter: Introduction to rclone

docs/howto/howto-use-rclone-with-cubbit-ds3.md

@@ -4,6 +4,15 @@
 
 This guide explains how to use the [rclone](https://rclone.org/) tool to access contents and backup data on a bucket of [Cubbit DS3 Object Storage](https://www.cubbit.io/).
 
+## Introduction to `rclone`
+
+From <https://rclone.org/>:
+
+> Rclone is a command-line program to manage files on cloud storage. It is a feature-rich alternative to cloud vendors' web storage interfaces.
+> [Over 70 cloud storage products](https://rclone.org/#providers) support rclone including S3 object stores, business & consumer file storage services, as well as standard transfer protocols.
+
+Official instructions for using rclone with Cubbit DS3 are available at <https://docs.cubbit.io/integrations/rclone>
+
 TODO
 
 <!-- EOF -->