Lots of additions:

- added unit tests
- renamed to yadu
- added gh test actions
- added docs

Makefile

@@ -0,0 +1,32 @@
+# Copyright © 2023 Thomas von Dein
+
+# This  module  is published  under  the  terms  of the  BSD  3-Clause
+# License. Please read the file LICENSE for details.
+
+#
+# no need to modify anything below
+
+all: buildlocal
+
+buildlocal:
+	go build
+
+clean:
+	rm -rf $(tool) coverage.out testdata t/out
+
+test: clean
+	go test $(ARGS)
+
+singletest:
+	@echo "Call like this: make singletest TEST=TestPrepareColumns ARGS=-v"
+	go test -run $(TEST) $(ARGS)
+
+cover-report:
+	go test -cover -coverprofile=coverage.out
+	go tool cover -html=coverage.out
+
+goupdate:
+	go get -t -u=patch ./...
+
+lint:
+	golangci-lint run -p bugs -p unused