Add note about custom webAppDirName breaking autodetection (#404)
Add note about custom webAppDirName breaking autodetection (#404)

* Add note about custom webAppDirName breaking autodetection

* Update USER_GUIDE.md

Co-authored-by: Chanseok Oh <4b19c7d703d69cdad83dba8e521398f0174467b1@google.com>

Co-authored-by: Chanseok Oh <4b19c7d703d69cdad83dba8e521398f0174467b1@google.com>
GoogleCloudPlatform/app-gradle-plugin,GoogleCloudPlatform/app-gradle-plugin,GoogleCloudPlatform/app-gradle-plugin