Extend Gitlab with a nice branch view / revision graph



I would like to extend gitlab. In my daily work with git i miss a really handy feature of tortoise git called revision graph. It shows the branches of the repository in a way so it’s much easier to understand how the branches relate to each other than using the git log command. You can see it here: https://stackoverflow.com/questions/38592542/need-help-to-understand-a-project-git-branch-tree

I would like to integrate the tool https://github.com/esc/git-big-picture

I tried to understand how I can write a plugin using https://docs.gitlab.com/ee/administration/plugins.html#gitlab-plugin-system

But I think it’s not possible to extend the web interface of my local gitlab server using the the gitlab plugin system, do I need to extend the gitlab source code for that?

How can I start to implement my feature?