chore: Create helm chart upgrade documentation

helm/flowforge/README.md

@@ -222,3 +222,83 @@ readinessProbe:
   successThreshold: 1
   failureThreshold: 3
 ```
+
+## Upgrading Chart
+
+### To 2.1.0
+
+Following database-related values have been removed from the chart:
+
+```
+forgedbName
+forge.dbUsername
+forge.dbPassword
+forge.postgres.host
+forge.postgres.port
+```
+
+All database configuration is maintained in the `postgresql` configuration block.
+Before upgrading to this version, please ensure that the [`postgresql`](#postgresql) block is correctly configured.
+Please pay attention to `forge.dbUsername` and `forge.dbPassword` values, as they are now part of the `postgresql.auth` block - `postgresql.auth.username` and `postgresql.auth.password` respectively.
+
+
+### To 2.0.0
+
+Together with new application features, this release updates the Helm sub-chart, Bitnami's Postgresql, version.
+If local PostgreSQL database instance is used, upgrading to this version, using our Helm chart, requires additional steps.
+
+1. Backup the database ([yq](https://mikefarah.gitbook.io/yq/#install) and [ghead](https://formulae.brew.sh/formula/coreutils) (part of `coreutils` package, MacOS only) tools are required)
+
+   For linux:
+
+      ```bash
+      DBPASSWORD=$(kubectl get cm flowforge-config -o jsonpath='{.data.flowforge\.yml}' | yq ".db.password") 
+      kubectl run -it --rm db-backup --env="PGPASSWORD=$DBPASSWORD" --image ubuntu/postgres:14-22.04_edge -- bash -c "pg_dump -h flowforge-postgresql -U forge flowforge" | head -n -2 > db.sql
+      ```
+
+   For macOS/BSD:
+
+      ```bash
+      DBPASSWORD=$(kubectl get cm flowforge-config -o jsonpath='{.data.flowforge\.yml}' | yq ".db.password")
+      kubectl run -it --rm db-backup --env="PGPASSWORD=$DBPASSWORD" --image ubuntu/postgres:14-22.04_edge -- bash -c "pg_dump -h flowforge-postgresql -U forge flowforge" | ghead -n -2 > db.sql
+      ```
+
+2. Obtain the PVC name which stores the database data
+Ó
+   ```bash
+   export POSTGRESQL_PVC=$(kubectl --namespace default get pvc -l app.kubernetes.io/name=postgresql,role=primary -o jsonpath="{.items[0].metadata.name}")
+   ```
+
+3. Delete postgresql statefulset and secret
+
+   ```bash
+   kubectl --namespace default delete statefulset.app flowforge-postgresql
+   kubectl --namespace default delete secret flowforge-postgresql
+   ```
+
+4. Get database image version and perform the upgrade  
+
+   ```bash
+   CURRENT_VERSION=$(kubectl --namespace defualt exec postgresql-postgresql-0 -- bash -c 'echo $BITNAMI_IMAGE_VERSION')
+
+   helm upgrade --install --atomic \
+      --namespace default  \ 
+      --values $path/to/your/values.yaml \
+      --set postgresql.primary.persistance.existingClaim=$POSTGRESQL_PVC \
+      --set postgresql.image.tag=$CURRENT_VERSION \
+      flowforge flowforge/flowforge
+   ```
+
+### To 1.12.0
+
+As of FlowFuse v1.12.0 the URL used to host the helm chart changed, so in order to upgrade from a previous 
+version you will need to update the repo.
+
+ - Run `helm repo remove flowforge`
+ - Run `helm repo add flowforge https://flowfuse.github.io/helm`
+
+ You can then run the following:
+
+- Run `helm repo update flowforge` to pull the latest version
+- Check the [README.md](https://github.com/FlowFuse/helm/blob/main/helm/flowforge/README.md) for any new options to configure in `customization.yml`
+- Run the `helm upgrade --install flowforge flowforge -f customization.yml`