[docs] add dokumentation about updating the modified nextcloud deck app

doc/src/SUMMARY.md

@@ -21,3 +21,4 @@
         - [Updates](./anleitung/updates.md)
         - [Rollbacks](./anleitung/rollback.md)
         - [MicroVM](./anleitung/microvm.md)
+        - [Update Nextcloud](./anleitung/update_nextcloud.md)

doc/src/anleitung/update_nextcloud.md

@@ -0,0 +1,16 @@
+### Updating nextcloud
+
+## Updating the draggable patch
+
+The draggable patch is a one line patch found in the deck repo under `src/components/cards/CardItem.vue`   
+Direct link: https://git.dynamicdiscord.de/ahtlon/deck/commit/77cbcf42ca80dd32e450839f02faca2e5fed3761   
+
+The easiest way to apply is
+1. Sync the repo with remote https://github.com/nextcloud/deck/tree/main
+2. Checkout the stable branch for the nextcloud version you need
+  - example `git checkout stable31`
+3. Apply the patch using `git cherry-pick bac32ace61e7e1e01168f9220cee1d24ce576d5e`
+4. Start a nix-shell with `nix-shell -p gnumake krankerl php84Packages.composer php nodejs_24`
+5. run `krankerl package`
+6. upload the archive at "./build/artifacts/deck.tar.gz" to a file storage (ask Ahtlon for access to the storj s3 or use own)
+7. Change url and sha in the nextcloud configuration.nix `deck = pkgs.fetchNextcloudApp {};`