docs(mkdocs): add common workflows section

docs/common-workflows/active-window-border.md

@@ -0,0 +1,40 @@
+# Active Window Border
+
+If you would like to add a visual border around the currently focused window,
+ensure the following options are defined in the `komorebi.json` configuration
+file.
+
+```json
+{
+  "active_window_border": true,
+  "active_window_border_colours": {
+    "single": {
+      "r": 66,
+      "g": 165,
+      "b": 245
+    },
+    "stack": {
+      "r": 256,
+      "g": 165,
+      "b": 66
+    },
+    "monocle": {
+      "r": 255,
+      "g": 51,
+      "b": 153
+    }
+  }
+}
+
+```
+
+It is important to note that the active window border will only apply to
+windows managed by `komorebi`.
+
+This feature is not considered stable and you may encounter visual artifacts
+from time to time.
+
+<!-- TODO: Record a new video -->
+
+[![Watch the tutorial
+video](https://img.youtube.com/vi/ywiAvoMV_gE/hqdefault.jpg)](https://www.youtube.com/watch?v=ywiAvoMV_gE)