tag deploys for appengine

Makefile

deploy: dependencies check
	# index must be clean (no modified files)
	git diff-index --quiet --cached HEAD
	# no uncomitted changes
	git diff-files --quiet

        # create a branch for the current version
	git branch -f deploy_`grep -E '^version: ' app.yaml | cut -d ' ' -f 2`
        # push current code to that branch
	git push -f . deploy_`grep -E '^version: ' app.yaml | cut -d ' ' -f 2`

        # install on AppEngine
	appcfg.py update .

        # upload tagged version to github
        git push origin deploy_`grep -E '^version: ' app.yaml | cut -d ' ' -f 2`

        # jetzt bitte zwitschern
        open https://zwitschr.hudora.biz/