Many shared hosts install gems locally. To allow them to load, put this at the top of your config/environment.rb file. Adjust as necessary.
ENV['GEM_HOME'] = '/home/username/ruby/gems'
ENV['GEM_PATH'] = '/home/username/ruby/gems:/usr/lib64/ruby/gems/1.8/:/usr/lib/ruby/gems/1.8/'
require 'rubygems'
Gem.clear_paths
Discussion
Many shared hosts install gems locally. To allow them to load, put this at the top of your config/environment.rb file. Adjust as necessary.
ENV['GEM_HOME'] = '/home/username/ruby/gems'
ENV['GEM_PATH'] = '/home/username/ruby/gems:/usr/lib64/ruby/gems/1.8/:/usr/lib/ruby/gems/1.8/'
require 'rubygems'
Gem.clear_paths