Add a sample makefile.

Makefile

@@ -0,0 +1,17 @@
+all: build
+
+OPTS ?= --progress
+Q ?= @
+SHOULD_UPDATE = ./bin/should-update
+DBDIR=/tmp/tests-on-dodb
+
+benchmark-cars:
+	$(Q)crystal build spec/benchmark-cars.cr $(OPTS)
+
+build: benchmark-cars
+
+wipe-db:
+	rm -r $(DBDIR)
+
+release:
+	make build OPTS="--release --progress"