补上cover图

src/main/java/com/fr/plugin/theme/original/OriginalTheme.java

@@ -37,7 +37,7 @@ public class OriginalTheme extends AbstractThemeVariousProvider {
 
     @Override
     public String coverPath() {
-        return "";
+        return "com/fr/plugin/theme/original/web/demo.png";
     }
 
 }