Build database-specific integrations

[timriley]

Right now we generate Rakefile that has postgres support only. It'd be nice to have a system that allows people to work with their favourite databases.

This should probably be provide by another gem.

[swistaczek]

It will be cool if there is any way to use mongoid with project but I am not sure what you think about this.

[GustavoCaso]

Hey, @timriley is there any one working on this one? if not I would like to help with this one