Update DIRECTORY.md (#68)

github-actions[bot] · web-flow · commit 62f594cb8b25 · 2026-07-28T12:32:13.000+03:00
Co-authored-by: github-actions[bot] &lt;github-actions[bot]@users.noreply.github.com&gt;
diff --git a/DIRECTORY.md b/DIRECTORY.md
@@ -1,5 +1,8 @@
 # Table of Contents
 
+## Data Structures
+- [Stack](data_structures/stack.jule)
+
 ## Math
 - [Abs](math/abs.jule)
 - [Ceil](math/ceil.jule)
