Many assets design question

Hi!

In my recent app I will have stuff like projects, references. Project
will have many assets like images and pdf’s. Reference will only have 1
asset - one image.

Is it good idea to build polymorphic resource like ASSET and try to put
every asset in there and have something like Attachable type = Project
or Reference??

If so, are there any examples that might help me?

PS.

I found something like http://sample.caboo.se/ - In this app
attachment_fu with resource_fu is being used to build this kind of
relationship.