Deployed Rails App on Staging and Production Environments

1) I looked at the mongrel.log file, the error message said that it
could not find staging.rb. So I created an empty staging.rb file under
config/environments directory.

2) staging configuration for socket value was set to the output of
locate mysql.sock.

3) The staging.log showed that require 'turn' statement in
environment.rb was missing the turn gem. I moved this statement to
development.rb, since it is required only for development.

Missing gem headaches: I also learned about rake freeze gem that allows
taking gems to the deployment environment. But I don't know if I freeze
a gem I will be able to upgrade it later. I will get this clarified from
Rails mailing list.

My emails are being sent, but when I signup I see the link as:

http://localhost.localdomain/activate/7fb260146d37cf5aec957fa0662d94c52a9f2488

http://#{ActionMailer::Base.smtp_settings[:domain]}/activate/#{user.activation_code} line in the rhtml template takes the smtp_settings defined for that environment. So
define the domain in staging.rb to fix this problem