Hallo,

after installing and trying vagrant,
using the quickstart instructions of

$ vagrant init debian/jessie64
$ vagrant up

"
The provider 'virtualbox' that was requested to back the machine
'default' is reporting that it isn't usable on this system. The
reason is shown below:

Vagrant could not detect VirtualBox! Make sure VirtualBox is properly installed.
Vagrant uses the `VBoxManage` binary that ships with VirtualBox, and requires
this to be available on the PATH. If VirtualBox is installed, please find the
`VBoxManage` binary and add it to the PATH environmental variable.
"

I didn't find a reference to the machine default so i could change it.
Also the README.md in the user docs seem to be an inheritance from an old ubuntu (precise) installation.

Conclusion: the virtualbox package should be depency (or maybe recommends); README.md file needs an update

mvg,
Wim Bertels