Syncing and linking

I'm already using Migrations, which is a fantastic feature. However, my live site's data is constantly changing. I frequently add more files and entries to the website, while my development site lags behind. It's not practical to add data manually to both sites. So, I've been looking for a more efficient solution, similar to something like 'rake db:restore' in Rails. I want a way to easily sync and update the data between my development and live sites.