added automatic cleanup link in hacking.md

CONTRIBUTING.md

@@ -64,6 +64,10 @@ size, disability, ethnicity, gender identity and expression, level of experience
 nationality, personal appearance, race, religion, or sexual identity and
 orientation.
 
+## About GNOME Calendar  
+
+Learn more about GNOME Calendar by reading our [HACKING.md](HACKING.md) file.
+
 ### Attribution
 
 This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,

HACKING.md

@@ -132,6 +132,17 @@ foo_bar_do_somthing_sync (a, 1, object, data,
                           &error);
 ```
 
+### Automatic Cleanup Variables
+
+GLib provides macros like `g_auto`, `g_autoptr`, and `g_autofree` for automatic 
+cleanup of variables when they go out of scope.
+
+Choose `g_auto` for non-pointer or stack-based types with custom cleanup, 
+`g_autoptr` for pointer types with type-specific cleanup functions, and 
+`g_autofree` for memory allocated with `g_malloc()` that should be freed using `g_free()`.
+
+For more details, visit the official documentation [here](https://docs.gtk.org/glib/auto-cleanup.html).
+
 # Contributing guidelines
 
 See CONTRIBUTING.md file for the contribution guidelines, and the Code of Conduct

README.md

@@ -6,6 +6,9 @@ effort.
 
 [![Flatpak](https://flathub.org/api/badge?svg&locale=en)](https://flathub.org/apps/details/org.gnome.Calendar)
 
+## Contributors Guide  
+
+Check out our [CONTRIBUTING.md](CONTRIBUTING.md) and [HACKING.md](HACKING.md) for more details.
 
 ## Useful links