Tools for doing it locally exist but how could it be done on a webserver and every time a commit is pushed?

References:

• https://github.com/thibaultmarin/hpp2plantuml
• https://support.circleci.com/hc/en-us/articles/360018860473-How-to-push-a-commit-back-to-the-same-repository-as-part-of-the-CircleCI-job