remove -f

Makefile

@@ -15,7 +15,7 @@ test:
 	env NAME=$(NAME) VERSION=$(VERSION) bats test/test.bats
 
 tag_latest:
-	docker tag -f $(NAME):$(VERSION) $(NAME):latest
+	docker tag $(NAME):$(VERSION) $(NAME):latest
 
 release: build test tag_latest
 	@if ! docker images $(NAME) | awk '{ print $$2 }' | grep -q -F $(VERSION); then echo "$(NAME) version $(VERSION) is not yet built. Please run 'make build'"; false; fi