Managing third-party javascript libraries

Hi guys,

I was wondering how I should manage external javascript libraries in
Rails 3.1.
For instance, say I want to use a jQuery plugin in my Rails project.
Since it's not a native Rails plugin, but a generic javascript
library, I would clone its github repository (e.g.
https://github.com/loopj/jquery-tokeninput), copy the necessary js
files into vendor/assets/javascripts/. So far so good, but doing this
every time I want to update those external plugins seems a bit like a
hassle. Is there a nicer way of doing this, like automating the
process? How do you do this?

Thanks.