Add mariadb.volumePermissions.image.pullPolicy

This fixes https://open.greenhost.net/openappstack/nextcloud/issues/28#note_7070

values.yaml

@@ -7,6 +7,10 @@ nextcloud:
   # Enable and configure MariaDB chart
   mariadb:
     enabled: true
+    # Needed to fix https://open.greenhost.net/openappstack/nextcloud/issues/28#note_7070
+    volumePermissions:
+      image:
+        pullSecrets: []
 
   # Use 2 GB of storage for NC storage (maybe make configurable later?)
   persistence: