SeedSow is a Ruby on Rails development tool which creates database seeds from two different sql dumps. Simply run the executable seedsow file1.sql file2.sql and observe the seed data you have added to the rails project.

cd $RAILS_ROOT
gem install seedsow
sqldump -uuser -ppass database > before.sql
# Open your app and create data however you like
sqldump -uuser -ppass database > after.sql
seedsow before.sql after.sql

Please feel free to fork this repository and add features or fix bugs as you see fit. Then submit a pull request, and I'll most likely merge your code.

SeedSow is licensed as Beerware