The QNAP storage server comes with a system called container-station which is really just a fancy UI over docker.
In this repository I have some of the docker compose files I have created to get the most out of my QNAP server.
First you will want to set up your machine to point to the docker instance running on QNAP. Here are some instructions: DockerSetup.md
Gogs - Container-Station has a way to load GitLab which is a Git repository. Useful for local development and code you do not want to exist on GitHub. However, Gitlab is bloated! It consumed 25% of the memory on QNAP server when I installed it. Gogs is much lighter weight and by using sqllite as a database it only requires 1 container to run. The result is that it only used 1% of QNAPs memory. It may not have some of the features of GitLab but it is perfect for home needs.