Added Github Security policy

SECURITY.md

@@ -0,0 +1,18 @@
+# Security Policy
+
+## Supported releases
+
+| Version | Supported          |
+| ------- | ------------------ |
+| 1.x.x   | :x:                |
+| 2.x.x   | :x:                |
+| 3.x.x   | :x:                |
+| 4.0.x   | :white_check_mark: |
+
+## Reporting an issue
+
+If you find a vulnerability with this package, please report it [here](https://github.com/nuxy/tidy-table/issues) for full disclosure.
+
+## Contributions
+
+If you fix a bug, or have a code you want to contribute, please send a pull-request with your changes. (Note: Before committing your code please ensure that you are following the [Node.js style guide](https://github.com/felixge/node-style-guide))