added coverage to readme

Author: joshika39

.gitignore

@@ -338,6 +338,5 @@ inspectcode
 
 *.GeneratedMSBuildEditorConfig.editorconfig
 
-
 .idea/.idea.idou/.idea/misc.xml
 .idea/.idea.idou/.idea/copilot.*

README.md

@@ -1,6 +1,7 @@
 # idou
 
 [![CodeFactor](https://www.codefactor.io/repository/github/kougen/idou/badge)](https://www.codefactor.io/repository/github/kougen/idou)
+![coverage](./badges/coverage.svg)
 
 `移動　(idō)` means migration in Japanese.