workbench

https://github.com/leadtune/workbench

Workbench strikes to reach a better balance between easy-to-read factory builders, ease of use, and robustness. Workbench doesn't use any fancy tricks. It's code is small and the average rubyist should have no trouble reading it. It exploits what ruby provides. Instead of operating on a proxy object, builders operate on the actual model. It's also ORM agnostic.