docs: add repo recovery documentation

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

docs/installation.md

@@ -280,6 +280,43 @@ Retrieve the API Key via the browser from a trusted client:
 
         {"result": "8ce6ae5d354a4365812b83140ed62e4b"}
 
+### Recovering a broken repo
+
+Currently Moonraker is deployed using `git`.  Without going into the gritty
+details,`git` is effectively a file system, and as such is subject to
+file system corruption in the event of a loss of power, bad sdcard, etc.
+If this occurs, updates using the `[update_manager]` may fail.  In most
+cases Moonraker provides an automated method to recover, however in some
+edge cases this is not possible and the user will need to do so manually.
+This requires that you `ssh` into your machine.  The example below assumes
+the following:
+
+- You are using a Raspberry Pi
+- Moonraker and Klipper are installed at the default locations in the `home`
+  directory
+- Both Moonraker and Klipper have been corrupted and need to be restored
+
+The following commands may be used to restore Moonraker:
+
+```shell
+cd ~
+rm -rf moonraker
+git clone https://github.com/Arksine/moonraker.git
+cd moonraker/scripts
+./install-moonraker.sh
+./set-policykit-rules.sh
+sudo systemctl restart moonraker
+```
+
+And for Klipper:
+
+```shell
+cd ~
+rm -rf klipper
+git clone https://github.com/Klipper3d/klipper.git
+sudo systemctl restart klipper
+```
+
 ### Additional Notes
 
 - Make sure that Moonraker and Klipper both have read and write access to the