chore(backups-cli): add usage to README

@xen-orchestra/backups-cli/README.md

@@ -12,6 +12,26 @@ Installation of the [npm package](https://npmjs.org/package/@xen-orchestra/backu
 > npm install --global @xen-orchestra/backups-cli
 ```
 
+## Usage
+
+```
+> xo-backups --help
+Usage:
+
+    xo-backups clean-vms [--merge] [--remove] xo-vm-backups/*
+
+      Detects and repair issues with VM backups.
+
+      Options:
+        -m, --merge     Merge (or continue merging) VHD files that are unused
+        -r, --remove    Remove unused, incomplete, orphan, or corrupted files
+
+
+    xo-backups create-symlink-index xo-vm-backups <field path>
+
+    xo-backups info xo-vm-backups/*
+```
+
 ## Contributions
 
 Contributions are _very_ welcomed, either on the documentation or on

@xen-orchestra/backups-cli/USAGE.md

@@ -0,0 +1,17 @@
+```
+> xo-backups --help
+Usage:
+
+    xo-backups clean-vms [--merge] [--remove] xo-vm-backups/*
+
+      Detects and repair issues with VM backups.
+
+      Options:
+        -m, --merge     Merge (or continue merging) VHD files that are unused
+        -r, --remove    Remove unused, incomplete, orphan, or corrupted files
+
+
+    xo-backups create-symlink-index xo-vm-backups <field path>
+
+    xo-backups info xo-vm-backups/*
+```