Is it possible to add a footer link on web app login page without forking mattermost-webapp?

Hi, everyone!
I currently add footer links by following Customizing Mattermost. But I have to do this all over again once I upgrade.
Is there any workaround?

Hi alzee,

as discussed in the community chat:
If you have a reverse proxy in front of Mattermost, you might want to inject some HTML using the reverse proxy.