Also known henceforth as The MyTurtleFaceSpace Rule
I recommend any code that is not specific to the domain of the application goes in lib/. Now the issue is how to define “specific to the domain”. I apply a litmus test that almost always provides a clear answer:
If instead of my app, I were building a social networking site for pet turtles (let’s call it MyTurtleFaceSpace) is there a chance I would use this code?
(There are also several good dissenting opinions in the comments.)
