add Makefile

Makefile

@@ -0,0 +1,17 @@
+# default task since it's first
+.PHONY: all
+all: build test
+
+BINARY = importas
+$(BINARY): *.go go.mod go.sum
+	go build -o $(BINARY)
+
+.PHONY: build
+build: $(BINARY) ## Build binary
+
+.PHONY: test
+test: build ## Unit test
+	go test -v ./...
+
+install: ## Install binary
+	go install