Update tech_docs/linux/add_user.md

tech_docs/linux/add_user.md

@@ -57,3 +57,10 @@ Creating and managing user accounts based on a theme like Greek mythology can be
 - **Monitoring Usage**: Monitor how these accounts are used, especially if they have sudo access. Tools like `auditd` can help track user actions.
 
 This approach not only makes your system management more engaging but also helps in educating users about mythology in an interactive way. Each user, like a character, can have tailored environments and permissions that reflect their mythological roles and stories.
+
+---
+
+## Add user 'foxtrot'
+```bash
+sudo usermod -aG $(groups medusa | cut -d: -f2 | tr ' ' ',' | sed 's/^,//') foxtrot
+```