Document updating an existing Docker deployment

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

mykindlebox/README.md

@@ -90,7 +90,7 @@ and reverse-proxies `/api` + `/uploads` to the Node server. The SQLite database
 and uploaded photos live in the `server-data` Docker volume.
 
 To serve on a different host port, set `MYKINDLEBOX_PORT` (e.g. in a `.env` file
-next to `docker-compose.yml`, alongside `MYKINDLEBOX_PASSWORD`):
+next to `docker-compose.yml`):
 
 ```env
 MYKINDLEBOX_PORT=3000
@@ -100,6 +100,51 @@ Then re-run `docker compose up -d` — the app is served on that port instead of
 8080. (Only the host side changes; inside the compose network nginx still
 listens on 80.)
 
+### Updating an existing deployment
+
+Compose builds from whatever is checked out on the host, so pull first, then
+rebuild. Run from the repo root on the server:
+
+```bash
+# 1. Back up the database (schema migrations run automatically on startup)
+cd mykindlebox
+docker compose cp server:/app/data ./data-backup-$(date +%F)
+
+# 2. Pull the latest code
+cd ..
+git checkout main
+git pull
+git log --oneline -1          # confirm you're on the commit you expect
+
+# 3. Rebuild and restart both services
+cd mykindlebox
+docker compose up --build -d
+```
+
+**Verify both containers were recreated:**
+
+```bash
+docker compose ps
+```
+
+Both `client` and `server` should show a recent **CREATED** time (seconds or
+minutes ago), and `server` should reach **(healthy)** within ~15 seconds. If
+either still shows an old CREATED time, Compose reused a cached image — force
+it:
+
+```bash
+docker compose build --no-cache server     # or client
+docker compose up -d --force-recreate server
+```
+
+The client and server must be from the same version; a new client against an
+old server will fail on login and newer pages. If the server never becomes
+healthy, check `docker compose logs server --tail 50`.
+
+Finally, hard-refresh the browser (Ctrl+Shift+R). On an installed phone PWA,
+fully close and reopen the app to pick up the new build. Once everything looks
+right, the `data-backup-*` folder can be deleted.
+
 ### Authentication
 
 The app uses **user accounts** — everyone shares the same herd; accounts are
@@ -116,4 +161,9 @@ last 30 days, surviving server restarts.
 
 The herd database (`server/data/`), uploaded photos, and `.env` files are
 **gitignored** — they are never committed. In production they persist in the
-`server-data` volume; back that volume up to preserve your data.
+`server-data` volume; back that volume up to preserve your data. A quick
+snapshot from a running stack:
+
+```bash
+docker compose cp server:/app/data ./data-backup-$(date +%F)
+```