Include example kustomization in Helm package

The goal has been to never accidentally include non-example
kustomizations, yet not to forget the example kustomization.

This however does not work the way we want it as expressed in
issue #157.

The problem is that .helmignore files are broken when it comes to
negation[1], which we tried to address in commit 25ee3b9, but that
approach also seems to fail.

Instead of relying on .helmignore, we'll now rely on the Makefile to
verify that no non-example kustomizations are in the directory. It's not
pretty, but it works and includes the example sections.

1: helm/helm#3622

Makefile

@@ -1,12 +1,29 @@
+ROGUE_KUSTOMIZE_FILES := $(shell find charts/timescaledb-single/kustomize/ -mindepth 2 -type f ! -path '*kustomize/example*')
+ROGUE_KUSTOMIZE_DIRS := $(shell find charts/timescaledb-single/kustomize/  -mindepth 1 -type d ! -path '*kustomize/example*')
+
+.PHONY: publish
+publish: publish-multinode publish-single
+
 .PHONY: publish-multinode
 publish-multinode:
 	helm package charts/timescaledb-multinode --destination charts/repo
 	helm repo index charts/repo
 
 .PHONY: publish-single
 publish-single:
+	@if [ "$(ROGUE_KUSTOMIZE_FILES)" != "" ]; then \
+		echo "Found non-example files in the timescaledb-single/kustomize directory"; \
+		echo "Please remove these files using 'make clean' or manually"; \
+		echo ""; \
+		echo "Unfortunately we cannot exclude these files in .helmignore due to"; \
+		echo "        https://github.com/helm/helm/issues/3622"; \
+		echo ""; \
+		exit 1; \
+	fi
 	helm package charts/timescaledb-single --destination charts/repo
 	helm repo index charts/repo
 
-.PHONY: publish
-publish: publish-multinode publish-single
+.PHONY: clean
+clean:
+	@if [ "$(ROGUE_KUSTOMIZE_FILES)" != "" ]; then rm -v $(ROGUE_KUSTOMIZE_FILES); fi
+	@if [ "$(ROGUE_KUSTOMIZE_DIRS)" != "" ]; then rmdir -v $(ROGUE_KUSTOMIZE_DIRS); fi

charts/timescaledb-single/.helmignore

@@ -1,5 +1,2 @@
 *.png
-*.crt
-*.key
-pgbackrest.conf
-credentials.conf
+