Setup Rails 3 App on Production Server (no compiler/root access)

I'm trying to set up a rails app on a production box (no compiler, no root access) that's running Mac OS X Server 10.6.6. It's got ruby 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0], and gem 1.3.5. However I need to install a newer version of rubygems because I need Rails 3 and Bundler. I can't update the system ruby or rubygems.

I tried installing a local version of rubygems (v 1.7.2) but 'gem -v' still returns 1.3.5. 'which 开发者_Python百科gem' definitely points to my local rubygems binary. What am I doing wrong?

Here's the output from 'gem env':

RubyGems Environment:

- RUBYGEMS VERSION: 1.3.5

- RUBY VERSION: 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0]

- INSTALLATION DIRECTORY: /.gem/ruby/1.8/gems

- RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby

- EXECUTABLE DIRECTORY: /.gem/ruby/1.8/gems/bin

- RUBYGEMS PLATFORMS:

- ruby

- universal-darwin-10

- GEM PATHS:

- /.gem/ruby/1.8/gems

- /.gem/ruby/1.8

- /Library/Ruby/Gems/1.8

- /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8

- GEM CONFIGURATION:

- :update_sources => true

- :verbose => true

- :benchmark => false

- :backtrace => false

- :bulk_threshold => 1000

- REMOTE SOURCES:

- http://gems.rubyforge.org/

Addition: When I run gem update --system I get the following error:

Updating RubyGems  
Updating rubygems-update  
Successfully installed rubygems-update-1.8.5  
Updating RubyGems to 1.8.5  
Installing RubyGems 1.8.5  
ERROR:  While executing gem ... (Errno::EACCES)  
    Permission denied - /Library/Ruby/Site/1.8/gauntlet_rubygems.rb  
RubyGems system software update

It still reports running version 1.3.5

Did you update your PATH to prefer your local gem 1.7.2 binary over the default? E.g. if you installed the 1.7.2 binary in ~/bin, you'd want to update your .bash_profile with export PATH="~/bin:$PATH".

Run which gem to find out which gem binary you are calling when you run gem env.

Can you install rvm on the server? If so then you can run inside your own app-specific rvm and have whatever gems/rubygems you want inside that.