update docs

docs/_index.md

-# IML BACKUP #
+# IML BACKUP
 
-Backup scripts using Restic (or Duplicity).
-
-Runs on Linux: CentOS, Debian, Manjaro, Ubuntu.
+Backup scripts to wrap Restic (or Duplicity).
+Runs on
+* Linux: (CentOS, Debian, Manjaro, Ubuntu)
+* MS Windows (by using compiled GNU tools eg. Cygwin or Mingw)
 
 📄 Source: <https://git-repo.iml.unibe.ch/iml-open-source/iml-backup/> \
 📜 License: GNU GPL 3.0 \
@@ -10,10 +11,10 @@ Runs on Linux: CentOS, Debian, Manjaro, Ubuntu.
 
 Supported backup clients:
 
-* Restic: <https://restic.net/>
-* Duplicity: <https://duplicity.gitlab.io/duplicity-web/>
+* Restic: <https://restic.net/> (default)
+* Duplicity: <https://duplicity.gitlab.io/duplicity-web/> ()
 
-# Why #
+# Why
 
 We rollout our linux systems automatically. We try not to configure third systems
 for backup, monitoring and other general services.