Basicaly we need to run the following command:
vagrant package --base <VM_NAME_ON_VIRTUALBOX> --vagrantfile <OUR_VAGRANT_FILE_PATH> --output <VAGRANT_BOX_OUTPUT_PATH/BOXNAME>
VM_NAME_ON_VIRTUALBOX is the name of our virtualbox machine as it's show on virtualbox gui, e.g.
OUR_VAGRANT_FILE_PATH this is the path to our
Vagrant file, thit's allow us to include our Vagrant configuration into our box.
VAGRANT_BOX_OUTPUT_PATH is the path where we want to save our
BOXNAME is the name that we want to give to our file.