add security metadata for vulnerability reporting

Author: msamsami

SECURITY.md

@@ -0,0 +1,19 @@
+# Security Policy
+
+## Reporting a Vulnerability
+
+If you think you found a vulnerability, and even if you are not sure about it, please report it right away by sending an email to: `hamid9 at outlook dot com`. Please try to be as explicit as possible, describing all the steps and example code to reproduce the security issue.
+
+## Vulnerability Disclosures
+
+Critical vulnerabilities will be disclosed via GitHub's [security advisory](https://github.com/LinearBoost/linearboost-classifier/security) system.
+
+## Public Discussions
+
+Please restrain from publicly discussing a potential security vulnerability.
+
+It's better to discuss privately and try to find a solution first, to limit the potential impact as much as possible.
+
+---
+
+Thanks for your help!