Update README.md

README.md

 
 * [AntiXSS](https://github.com/voku/anti-xss) - A library that tries to preventing Cross-Site Scripting (XSS) attacks by blacklisting.
 * [Halite](https://paragonie.com/project/halite) - A simple library for encryption using [libsodium](https://github.com/jedisct1/libsodium).
+* [Observer](https://github.com/sanks205/getobserver) - An offline, single-binary CLI that scans a codebase for security and production-health issues and outputs one HTML report.
 * [Optimus](https://github.com/jenssegers/optimus) - Id obfuscation based on Knuth's multiplicative hashing method.
 * [OWASP](https://owasp.org/) - Explore the world of cyber security.
 * [PHPGGC](https://github.com/ambionics/phpggc) - A library of PHP unserializable payloads along with a tool to generate them.