Add a Make target for testing the configuration

Makefile

@@ -0,0 +1,11 @@
+IMAGE = homeassistant/home-assistant
+HASS_BIN = python -m homeassistant
+VOLUMES = $(PWD):/config /etc/localtime:/etc/localtime:ro
+HASS = docker run -it --rm \
+	$(addprefix -v ,$(VOLUMES)) \
+	$(IMAGE) $(HASS_BIN) \
+	--config /config
+
+.PHONY: test
+test:
+	@$(HASS) --script check_config --files