Un-bloating models in rails 3.1

Just learning rails, developing first app and having trouble finding a straight answer to this question!

I want to keep my models as lean as possible and really only want to use them to represent objects that I might want to render in my views. Therefore, I want to remove some of the logic from one particular model and store it in a separate file. I have seen numerous guides (on this site and others) that suggest the following;

never "require" anything from inside a rails app
Store additional files in the lib folder - they used to be auto loaded in older rails releases but now you need to add an extra line in a config file to get this to happen (Example.

So I added the line, stuck the file in the lib folder, and it all worked fine. So on to the question;

I can't shake the feeling that the fact that I had to go and put some bespoke code into the config file means I'm doing this wrong (given convention over configuration). Why are people having to faff around editing configuration files to get rails to do something so basic?

Is that the best way or are there additional considerations that I'm just not seeing? Should I in fact be creating an "extras" directory rather than still sticking things in lib?

If anyone can point me in the direction of a definitive article on the matter I'd be much obliged!

Solution

There is nothing wrong with having non active record models in the model folder. If your domain is best modeled by a business logic layer and a persistence layer, then model it that way in your model folder with appropriate naming conventions. Personally I wouldn't be overly concerned with getting it perfect. Try something and see how you like it.. learn from your mistakes and keep getting better! Above all, enjoy the process.