Create SECURITY.md

SECURITY.md

+# RavadaVDI Security
+
+We take security very seriously. We welcome any peer review of our 100% open source code to ensure nobody's Ravada is ever compromised or hacked.
+
+## Reporting a Vulnerability
+
+So, you think you found a vulnerability? Well, please let us know!
+Please open up an [issue][1] and try to provide as much information as possible.
+
+[1]: https://github.com/UPC/ravada/issues/new?assignees=&labels=&template=bug_report.md&title=