Updating the readme with new nulecule dev box
Updating the readme with new nulecule dev box

Signed-off-by: Lalatendu Mohanty <51e26f8eb794e7391b5ea8128d9ade5c4c5ae20b@redhat.com>

goern/centos7-container-app-vagrant-box,goern/centos7-container-app-vagrant-box,bexelbie/centos7-container-app-vagrant-box,bexelbie/centos7-container-app-vagrant-box