Added schema0 (how works plugins)

Author: sea5kg

README.md

@@ -17,6 +17,10 @@ Pluging for scripting by python3 in Unigine Editor https://unigine.com/get-unigi
 
 [here](https://sea-kg.com/files/unigine-plugins/UnigineEditorPlugin_Python3Scripting/v2.17/)
 
+## Plugins system of Unigine
+
+![schema0](docs/plugins/Sea5kg/Python3Scripting/schema0.png)
+
 
 ## build