[stable/drupal] Fix chart not being upgradable

stable/drupal/Chart.yaml

@@ -1,5 +1,5 @@
 name: drupal
-version: 1.1.4
+version: 2.0.0
 appVersion: 8.6.1
 description: One of the most versatile open source content management systems.
 keywords:

stable/drupal/README.md

@@ -164,3 +164,15 @@ $ helm install --name my-release --set persistence.drupal.existingClaim=PVC_NAME
 
     This will mount the `drupal-data` volume into the `hostPath` directory. The site data will be persisted if the mount path contains valid data, else the site data will be initialized at first launch.
 1. Because the container cannot control the host machine’s directory permissions, you must set the Drupal file directory permissions yourself and disable or clear Drupal cache. See Drupal Core’s [INSTALL.txt](http://cgit.drupalcode.org/drupal/tree/core/INSTALL.txt?h=8.3.x#n152) for setting file permissions, and see [Drupal handbook page](https://www.drupal.org/node/2598914) to disable the cache, or [Drush handbook](https://drushcommands.com/drush-8x/cache/cache-rebuild/) to clear cache.
+
+## Upgrading
+
+### To 2.0.0
+
+Backwards compatibility is not guaranteed unless you modify the labels used on the chart's deployments.
+Use the workaround below to upgrade from versions previous to 2.0.0. The following example assumes that the release name is drupal:
+
+```console
+$ kubectl patch deployment drupal-drupal --type=json -p='[{"op": "remove", "path": "/spec/selector/matchLabels/chart"}]'
+$ kubectl delete statefulset drupal-mariadb --cascade=false
+```

stable/drupal/templates/deployment.yaml

@@ -8,6 +8,10 @@ metadata:
     release: "{{ .Release.Name }}"
     heritage: "{{ .Release.Service }}"
 spec:
+  selector:
+    matchLabels:
+      app: {{ template "drupal.fullname" . }}
+      release: "{{ .Release.Name }}"
   replicas: 1
   template:
     metadata: