title: RVM and automatically switching gemsets
body: <p>Is it possible to have rvm know which gemset it should be using while navigating under a certain directory, much in the same way you can have git the current branch's information just by navigating under that directory?  </p>
  
  <p>I understand how git works that way since each directory has its own .git directory in the root, but didn't know if it was possible since .rvm is more of a user-wide configuration.  Or perhaps the answer is to make a .rvm file within each directory? </p>