updated readme

README.md

@@ -405,6 +405,33 @@ Some applications have trouble understanding synthesized key events, especially
 Wayland. `keypress_delay_ms` can be used to workaround the issue.
 See [#179](https://github.com/k0kubun/xremap/issues/179) for the detail.
 
+### Shared data field
+
+You can declare data that does not directly go into the config under the `shared` field.  
+This can be usefull when using Anchors and Aliases.  
+For more information about the use of Yaml anchors see the [Yaml specification](https://yaml.org/spec/1.2.2/#3222-anchors-and-aliases).
+
+#### example:
+```yaml
+shared:
+  terminals: &terminals # The & Symbol marks this entry as a Anchor
+    - Gnome-terminal
+    - Kitty
+  
+  some_remaps: &some_remaps
+    Ctrl-f: C-right
+    Alt-b: C-up
+
+keymap:
+  applications:
+    only: *terminals # we can reuse the list here
+    not: *browsers
+  remap:
+    <<: *some_remaps # or we can reuse a map here. If there are duplicate keys, the key in the alias will be ignored.
+    Alt-f: C-right
+    Alt-b: C-left
+```
+
 ## License
 
 `xremap` is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).