add note for deployment

README.md

@@ -11,6 +11,9 @@ npm run serve
 ```
 
 ### Compiles and minifies for production
+
+If you are deploying in a subdirectory, add it to `publicPath` in vue.config.js, eg: `publicPath: "/app/time-tracker/",`
+
 ```
 npm run build
 ```