Modify root URL generated by <%= link_to %>

Is there a way to manually specify the root url that a <%= link_to %>
generates? So i can make an auto generated url that used to go to
mywebsite.myhost.com/comments be go to example.com/comments ?

The reason, if you’re wondering is that I have hosting at a site and my
domain forwarded and masked through go-daddy. This means when you go to
example.com you are seeing content on mywebsite.myhost.com but the url
shows up as example.com. The problem comes when you click on a link for
lets say comments, for whatever reason instead of showing
example.com/comments in the url it just shows example.com. If you type
example.com/comments directly into the address bar though, everything
works great you get the content you expect and the url you expect. So
how can i make my <%= link_to %>'s use example.com as the base url
instead of mywebsite.myhost.com???

I tried setting the default_url_options in my config/environments.rb
like this:

config.action_controller.default_url_options = { :host =>
example.com’}

but I get this error when i restart my server I get this error, is there
another way to accomplish this taks?

/opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:530:in
send': undefined method default_url_options=’ for
ActionController::Base:Class (NoMethodError)
from
/opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:530:in
initialize_framework_settings' from /opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:529:in each’
from
/opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:529:in
initialize_framework_settings' from /opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:526:in each’
from
/opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:526:in
initialize_framework_settings' from /opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:154:in process’
from
/opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:112:in
send' from /opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/initializer.rb:112:in run’
… 27 levels…
from
/opt/local/lib/ruby/gems/1.8/gems/rails-2.2.2/lib/commands/server.rb:49
from
/opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in
gem_original_require' from /opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in require’
from script/server:3

Ruby 1.8.6
Rails 2.2.2

Still haven’t been able to figure this out. Instead i just changed the
nameserver on go-daddy to point at my RoR host’s servers. So even though
i can’t host the DNS on the same server, i can have the DNS point at my
RoR host server. Learn something new every day!