I am making modifications to /grails-app/views/index.gsp.
When I save the file and refresh http://localhost:8080/index.gsp in Firefox, I am getting an old version of the
If you simply want to disable cache for your browser while development, you can use Web Developer add on for Firefox:
https://addons.mozilla.org/en-US/firefox/addon/60
Install this add on & choose "Disable cache". Remember, that will disable caching for all the websites.