* Add persistence to the default Docker container
This sets a default volume of `/data` for the Docker container.
This allows for persistence when using the default SQLite database, and the option of mounting the volume to the host for backing up.
* Add -v flag description
Co-authored-by: Jesús Espino <jespinog@gmail.com>
This commit recreates the entire dockerfile for several reasons:
* compile focalboard instead of downloading and extracting a tarball
* it uses an alpine image and intermediate containers to obtain a much
smaller image
* run focalboard as user inside the container instead of root
Co-authored-by: Jesús Espino <jespinog@gmail.com>
