updated readme

readme.md

@@ -24,6 +24,16 @@ Root
     └───[each script folder].user.js
 ```
 
+if there is an error compiling a file, an `error.log` will be placed inside the source folder:
+
+```text
+Root
+├───<package.json/etc>
+└───scripts
+    └───[each script folder]
+        └───error.log
+```
+
 ## Command Line Options
 
 ```text