add git commit hash as docker tag (#47)

In addition to the main, pr and release tags, add the git short hash as an image tag for maximum stability (particularly of main commits)

Author: amitschang

Makefile

@@ -38,8 +38,11 @@ rendersvc.image: python
 	cd components/python/rendersvc && docker build $(DOCKER_BUILD_OPTS) -t $(REPO)/rendersvc:$(VTAG) -f docker/Dockerfile .
 
 PUSH_TARGETS=$(addsuffix .push,$(IMAGE_COMPONENTS)) keystone.push dashboard.push dashboard-build.push web.push graphql.push rendersvc.push
+HASHTAG=$(shell git rev-parse --short=7 HEAD)
 %.push: %.image
+	docker tag $(REPO)/$(subst .push,,$@):$(VTAG) $(REPO)/$(subst .push,,$@):$(HASHTAG)
 	docker push $(REPO)/$(subst .push,,$@):$(VTAG)
+	docker push $(REPO)/$(subst .push,,$@):$(HASHTAG)
 
 images: $(IMAGE_TARGETS)