diff --git a/courses/security/.DS_Store b/courses/security/.DS_Store
deleted file mode 100644
index 1f64dbc..0000000
Binary files a/courses/security/.DS_Store and /dev/null differ
diff --git a/mkdocs.yml b/mkdocs.yml
index 91737c9..ce865f4 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -24,4 +24,10 @@ nav:
     - Usage of Big Data techniques: big_data/usage.md
     - Evolution of Hadoop: big_data/evolution.md
     - Architecture of Hadoop: big_data/architecture.md
-    - Tasks and conclusion: big_data/tasks.md 
+    - Tasks and conclusion: big_data/tasks.md
+- Security:
+    - Inro: security/intro.md
+    - Fundamentals of Security: security/fundamentals.md
+    - Network Securuty: security/network_security.md
+    - Threat, Attacks & Defences: security/threats_attacks_defences.md
+    - Writing Secure code: security/writing_secure_code.md