self-hosted runners

• Set up different types of servers for continuous integration using Ansible playbooks
• Documentation for remote systems such as SURF HPC-cloud, as well as local systems via Docker, VirtualBox, and Vagrant
• Includes examples for continuous integration servers with GPU

Additional repositories:

• https://github.com/ci-for-science/example-gpu-houston
• https://github.com/ci-for-science/example-hello-world
• https://github.com/ci-for-science/example-python-1
• https://github.com/ci-for-science/example-python-monte-carlo-pi