Basically, it runs docker containers using chroot to prove that it's possible.
Docker uses Layered Filesystems (Multiple Filesystems mounted under the same folder on top of one another), something that used to be mostly used when you have a read only Filesystem, like a cdrom, then mount a writeable folder over the same mount point to make that folder writeable.
Bocker does a similar mounting of the layers with chroot to run docker containers.
https://github.com/p8952/bocker
Basically, it runs docker containers using chroot to prove that it's possible.
Docker uses Layered Filesystems (Multiple Filesystems mounted under the same folder on top of one another), something that used to be mostly used when you have a read only Filesystem, like a cdrom, then mount a writeable folder over the same mount point to make that folder writeable.
Bocker does a similar mounting of the layers with chroot to run docker containers.