docker.env should be the environment file located in this repository, customized to your settings. The env file is self-documenting so I don't need to go in any detail here.
We recommend using Docker as it provides better security (we suck in security, so that's why) and we are constantly updating Segfautilities. Docker makes it easy to update the program.
If you're using Portainer, you should know how to add Segfautilities.