improvements

I extended your script for my purposes and wanted to let you know about it, maybe you can use some of the pars, too. If not, thanks for the basis anyway ;)

My improvements so far:
* a filter for event type == "push" - if webhooks are correctly set up, this should not be needed
* I added the ProxyFix from werkzeug since I run the script behind nginx as a reverse proxy (since it can be dangerous, it must be enabled via environment variable)
* the repositorys can be configured to only act on specific branches