add postgres chart example values

values/postgresql/prod-values.example.yaml

@@ -0,0 +1,15 @@
+postgresql:
+  fullnameOverride: postgresql
+  ####### Uncomment and set these creds.
+#  auth:
+#    postgresPassword:
+#    username:
+#    password:
+#    database:
+
+  primary:
+    persistence:
+      # Create a pv and pvc for storing data. Refer to pv_pvc.yaml
+      existingClaim: postgresql-pv-claim
+  volumePermissions:
+    enabled: true

values/postgresql/pv_pvc.yaml

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+apiVersion: v1
+kind: PersistentVolume
+metadata:
+  name: postgresql-pv
+  labels:
+    type: local
+spec:
+  storageClassName: manual
+  capacity:
+    storage: 10Gi
+  accessModes:
+    - ReadWriteOnce
+  hostPath:
+    path: "/mnt/data"
+
+---
+
+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: postgresql-pv-claim
+spec:
+  storageClassName: manual
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      storage: 10Gi