The easiest way to generate SealedSecrets is to create a file called something.secret.yaml, and then use make something.sealed-secret.json to generate the SealedSecret using kubeseal. Make sure to put the Namespace in the Secret yaml, as SealedSecret resources are namespace-specific!
APP=someapp
k exec -it psql-0 -- /scripts/createdb.sh $APP | kubeseal -n $APP