update README, add Donate section

Author: beicause

README.md

@@ -15,16 +15,19 @@ vscode extension for generate call graph in [graphviz dot language](https://www.
 4. Click `save dot file` or `save as svg` in the bottom left corner to save the graph
 5. Add `.callgraphignore` file in your project root directory to ignore some files or folders in workspace (the syntax is the same as `.gitignore`)
 
-## Extra configuration
-- **Max depth**: You can set the max depth at the `Call-graph: Max Depth` setting in the editor settings session. Note that it applies for both incoming and outgoing call graphs.
+## Configuration
+You can configure `ignoreFile`(.callgraphignore by default), `maxDepth` and `saveDir` for svg or dot in settings. See the descriptions in setting.
 
 ## How it works
 It depends `vscode.provideOutgoingCalls` and `vscode.provideIncomingCalls` built-in commands( the same with `Show Call Hierarchy` command, not available for some language server ).
 
-### For more information
+## For more information
 * Also developed by me for preview and edit graphviz file:
   - [Graphviz Viewer Online](https://graphviz.net)
   - [Graphviz Viewer in Google Play](https://play.google.com/store/apps/details?id=indie.haozi.gvviewer)
 * [GitHub](https://github.com/beicause/call-graph)
 
+## Donate
+[Donate me via Paypal](https://paypal.me/beicause). Thank you for you support to this project and my open source works.
+
 **Enjoy!**