Hey I actually do the same in a mobile app. I dump everything into a local database, when they are connected to the internet it syncs, lets it work offline.
In my workflow, I PULL when they initial get online and MERGE non conflicting changes and ACCEPT the changes with the latest timestamp if there is a conflict.
It's not perfect and people still complain, to do it cleanly I would need to prompt the user which change to take but I haven't figured out a clean way to do that yet.
