docs: link Mastering OpenDoor article series

Author: stanislav-web

README.md

@@ -49,6 +49,15 @@ It helps security researchers, penetration testers, bug bounty hunters, DevSecOp
 
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+## 🎓 Mastering OpenDoor
+
+Hands-on article series for learning OpenDoor through reproducible, authorized web reconnaissance workflows.
+
+- [Part 1 — Context-Aware Web Recon Beyond Directory Brute Force](https://medium.com/@stanisov/mastering-opendoor-context-aware-web-recon-beyond-directory-brute-force-part-1-cc13eda8cd3d)
+- [Series companion page](https://opendoor.readthedocs.io/guides/mastering-opendoor/)
+
+---
+
 ## ✨ Features
 
 - directory discovery;