tell travis to run the tests

Makefile

@@ -1,8 +1,12 @@
 # These targets are not files
 .PHONY: tests
 
-tests:
-	./bin/test
+test: test-cedar-14
+
+test-cedar-14:
+	@echo "Running tests in docker (cedar-14)..."
+	@docker run -v $(shell pwd):/buildpack:ro --rm -it -e "STACK=cedar-14" heroku/cedar:14 bash -c 'cp -r /buildpack /buildpack_test; cd /buildpack_test/; test/run;'
+	@echo ""
 
 tools:
 	git clone https://github.com/kennethreitz/pip-pop.git