Another option would be the successor to TFS, now known as Azure DevOps. This solution is essentially the same TFS that you have grown to know and "love", while adding the option to use GitHub, a Git Repository that is private to your organization, or VSTS as your code repository, while still tracking the work items, builds, code changes, and being able to tie them all together, in much the same way that you already do. The latest version also has Markdown support, and the ability to build your change management plan by simply linking the work items, bugs and code changes together under a given User Story, even in a hybrid environment, where some stuff is in the cloud, but there's other stuff that get's kept inside the company firewall.
There's so much more than would do the solution justice here. Go check out Microsoft Azure DevOps, and see for yourself just how versatile it is!