README update.

Author: iwatkot

README.md

@@ -229,6 +229,10 @@ The tool now has a Modder Toolbox, which is a set of tools to help you with vari
 
 ### Tool Categories
 Tools are divided into categories, which are listed below.
+
+#### For custom schemas
+- **Tree Schema Editor** - allows you to view all the supported trees models and select the ones you need on your map. After it, you should click the Show updated schema button and copy the JSON schema to the clipboard. Then you can use it in the Expert settings to generate the map with the selected trees.
+
 #### For Textures and DEM
 - **GeoTIFF windowing** - allows you to upload your GeoTIFF file and select the region of interest to extract it from the image. It's useful when you have high-resolution DEM data and want to create a height map using it.
 
@@ -568,3 +572,4 @@ But also, I want to thank the people who helped me with the project in some way,
 - [Lucandia](https://github.com/Lucandia) - for the awesome StreamLit [widget to preview STL files](https://github.com/Lucandia/streamlit_stl).
 - [H4rdB4se](https://github.com/H4rdB4se) - for investigating the issue with custom OSM files and finding a proper way to work with the files in JOSM.
 - [kbrandwijk](https://github.com/kbrandwijk) - for providing [awesome tool](https://github.com/Paint-a-Farm/satmap_downloader) to download the satellite images from the Google Maps and giving a permission to modify it and create a Python Package.
+- [Maaslandmods](https://github.com/Maaslandmods) - for the awesome idea to edit the tree schema in UI, images and code snippets on how to do it.