Merge pull request #247 from jrop/patch-1

Add Slack Nebula to "VPN" section

readme.md

@@ -170,6 +170,7 @@ You will notice some items on this list have a :star2: next to them. Items with
 - [n2n](https://github.com/ntop/n2n) Peer-to-peer VPN
 - [PeerVPN](https://peervpn.net/) PeerVPN is a software that builds virtual ethernet networks between multiple computers.
 - [OpenVPN](https://openvpn.net/) :star2: OpenVPN provides flexible VPN solutions to secure your data communications, whether it's for Internet privacy, remote access for employees, securing IoT, or for networking Cloud data centers.
+- [Nebula](https://github.com/slackhq/nebula) A scalable overlay networking tool with a focus on performance, simplicity and security
 - [Pritunl](https://pritunl.com/) Enterprise Distributed OpenVPN and IPsec Server
 - [WireGuard VPN](https://www.wireguard.com/) WireGuard is an extremely simple yet fast and modern VPN that utilizes state-of-the-art cryptography. It aims to be faster, simpler, leaner, and more useful than IPSec.
 - [sshuttle](https://github.com/sshuttle/sshuttle) Transparent proxy server that works as a poor man's VPN.