Gem environment switched from Ruby 1.8.7 back to system loaded Ruby 1.8.6

So, I am relatively new to unix and Ruby on Rails. I'm currently working on the Ruby on Rails Tutorial. I'm using OS 10.5.8. I had installed Ruby 1.8.7 and RubyGems 1.3.5 into /usr/local/bin/ and had installed Git as well. Everything was working fine and I was charging ahead.

Then I ended a shell session, came back to it and the whole RubyGem prefix and executable changed to the system installed: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby and started running Ruby 1.8.6 and RubyGems 1.0.1.

What happened? How do I get back to my original path to the Ruby 1.8.7 and RubyGem 1.3.5. Or should I just try and upgrade the existing path to Ruby 1.8.7, etc.? Could rvm help this problem and how?

My path looks like: /usr/local/git/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin:/usr/local/git/bin

And my gem environment is:
RubyGems Environment:
- RUBYGEMS VERSION: 1.0.1 (1.0.1) - RUBY VERSION: 1.8.6 (2009-06-08 patchlevel 369) [universal-darwin9.0] - INSTALLATION DIRECTORY: /Library/Ruby/Gems/1.8 - RUBYGEMS PREFIX: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby - RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby - RUBYGEMS PLATFORMS:

- ruby
- universal-darwin-9

• GEM PATHS:
  • /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8
  • /Library/Ruby/Gems/1.8
• GEM CONFIGURATION:
  • :update_sources => true
  • :verbose => true
  • :benchmark => false
  • :backtrace => false
  • :bulk_threshold => 1000
• REMOTE SOURCES:
  • http://gems.rubyforge.org