[rufugee]

No offense, but this is absolutely bad advice to a newbie programmer. First, mongo_mapper is virtually undocumented, whereas ActiveRecord has oodles of documentation and examples. You'll spend a order of magnitude more time trying to learn to use both MongoDB and mongo_mapper effectively than you will writing a proper set of migrations.

Second, I'm tired of all the NoSQL hype. I've worked on a project with MongoDB and MongoMapper, and the combination caused more problems than it solved. If you want cutting edge and all that comes with that, go with Mongo. Otherwise, if you'd prefer to focus on problems in the domain you're trying to solve and not the technology you're trying to solve it with, go with something relational and tried and true (PostgreSQL, if I were deciding).

[binspace]

I'm sick of all of the hype (for the past 20+ years) that relational databases is the only data storage technology you need.

When all you have is a hammer...