Add CHANGELOG.md and vlan command breaking change.

CHANGELOG.md

@@ -0,0 +1,20 @@
+# Change Log
+
+## [0.x] - 2026-xx-XX
+
+## Added
+
+## Changed
+
+## Fixed
+
+## Breaking changes
+
+- Config
+  - VLAN don't accept port `u`-suffix anymore.
+    So `vlan 1 4u` is not valid anymore.
+    Replace it with `vlan 1 4`.
+
+## [v0.1_aplha] - 2025-11-03
+
+First release.