title: rbenv: multiple instances of SAME ruby
body: <p>I have two scripts which require the same version of Ruby.  However, each script also requires a DIFFERENT version of a gem (nokogiri).  One of the scripts will run with both versions of nokogiri (1.6.2.1 and 1.6.1).  However the other script will ONLY run with version 1.6.1; and if 1.6.2.1 is installed, the script will not execute normally.</p>
  
  <p>I know how to install multiple versions of Ruby with rbenv.  But is it possible to install multiple instances of the SAME version of Ruby (2.1.2)?  If so, how?</p>