docs(readme): add tool description

Signed-off-by: r3drun3 <simone.ragonesi@sighup.io>

README.md

@@ -1,8 +1,14 @@
 # NostrO
 [![License: ODbL](https://img.shields.io/badge/License-PDDL-brightgreen.svg)](https://opendatacommons.org/licenses/pddl/)  
 
-Nostr Osint Tool  
+**Nostr Osint Tool**  
 
 
-<img src="images/logo.png" alt="Nostr Logo" width="300" height="200">
+<img src="images/logo.png" alt="Nostr Logo" width="300" height="200">  
+
+`NostrO` is designed for conducting *Open Source Intelligence* (OSINT) operations on *Nostr*.  
+NostrO facilitates operations such as keyword search on filtered user notes, and more.  
+
+> **Note**
+> The tool is currently in the experimental phase, and we welcome pull requests and contributions!