If you've got the basics of Ruby down, get this book and take it to the next level
As for the gems in rails..study their code, learn what they try to do, then program it yourself, else you might spend forever fighting with poorly documented and fragile gems, that were never really intended for long term production use anyway..
just my 2 cents..
I just started it last week and have come to really appreciate ruby. My code doesn't look like python anymore :)