How to set RUBY EXECUTABLE path in Ruby Gems Environment

I have ruby 2 version in my Mac which are 1.8.6 and 1.8.7.
I would like to set Rubygems environment to point to Ruby 1.8.7.

Anyone know this issure???

ubyGems Environment:

  • RUBYGEMS VERSION: 1.3.5
  • RUBY VERSION: 1.8.6 (2008-08-11 patchlevel 287) [universal-
    darwin9.0]
  • INSTALLATION DIRECTORY: /Library/Ruby/Gems/1.8
  • RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/
    Versions/1.8/usr/bin/ruby
  • EXECUTABLE DIRECTORY: /usr/bin
  • RUBYGEMS PLATFORMS:
    • ruby
    • universal-darwin-9
  • GEM PATHS:
    • /Library/Ruby/Gems/1.8
    • /Users/panu/.gem/ruby/1.8
    • /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/
      ruby/gems/1.8
  • GEM CONFIGURATION:
  • REMOTE SOURCES: