.goreleaser: add upgrade section (#2820)

.goreleaser.yml

@@ -8,6 +8,33 @@ before:
 release:
   prerelease: auto
   draft: true
+  header: |
+    ## Upgrade
+
+    Please follow the steps outlined in the [upgrade guide](https://headscale.net/stable/setup/upgrade/) to update your existing Headscale installation.
+
+    **It's best to update from one stable version to the next** (e.g., 0.24.0 → 0.25.1 → 0.26.1) in case you are multiple releases behind. You should always pick the latest available patch release.
+
+    Be sure to check the changelog above for version-specific upgrade instructions and breaking changes.
+
+    ### Backup Your Database
+
+    **Always backup your database before upgrading.** Here's how to backup a SQLite database:
+
+    ```bash
+    # Stop headscale
+    systemctl stop headscale
+
+    # Backup sqlite database
+    cp /var/lib/headscale/db.sqlite /var/lib/headscale/db.sqlite.backup
+
+    # Backup sqlite WAL/SHM files (if they exist)
+    cp /var/lib/headscale/db.sqlite-wal /var/lib/headscale/db.sqlite-wal.backup
+    cp /var/lib/headscale/db.sqlite-shm /var/lib/headscale/db.sqlite-shm.backup
+
+    # Start headscale (migration will run automatically)
+    systemctl start headscale
+    ```
 
 builds:
   - id: headscale