Breaking changes
- `use_sudo` option is no longer supported. It offered questionable security,
and complicated the code unnecessarily. If 'securely run as normal user with
sudo' is a required feature, we can re-implement it securely later.
- If a path in `readonly_paths` does not exist, spawning user will now fail.
New features
- **Dynamic users** support, creating users as required with their own
persistent homes with systemd's [dynamic users](http://0pointer.net/blog/dynamic-users-with-systemd.html)
feature. Useful for using with tmpnb.
- **Add additional properties** to the user's systemd unit with `unit_extra_properties`.
Thanks to [kfix](https://github.com/kfix) for most of the work!
Bug fixes
- If a user's notebook server service is already running, kill it before
attempting to start a new one. [GitHub Issue](https://github.com/jupyterhub/systemdspawner/issues/7)
Dependency changes
- Python 3.5 is the minimum supported Python version.
- JupyterHub 0.9 is the minimum supported JupyterHub version.
- Tornado 5.0 is the minimum supported Tornado version.