如何使用rbenv的多个rails版本？

Is it possible to use multiple versions of rails using rbenv (e.g. 2.3 and 3.1)? This was easy with gemsets in rvm, but I'm wondering what the best way is to do it now that I've switched to rbenv (also, I'm looking for a way to do it without rbenv-gemset).Is it possible to use multiple versions of rail