Helm Values.yml missing storeageClass (On stack w more than 1 default StoreageClass)

[doug62]

A helm install on a stack with more than 1 default storeage class produces an error - the following fix corrects it.

persistence:
size: "2Gi"
annotations: {}
storageClass: - this is a value that should be documented/included in values.yaml

[funkypenguin]

Thanks for pointing this out, @doug62! Once merged, #44 will include a reference to persistence.storageClass in values.yaml. The value is documented (along with other customisations) in the chart README though :)