Every developer on my team has their own local configuration. That configuration information is stored in a file called devtargets.rb which is used in our rake
Common practice seems to be to create a devtargets.default.rb and commit it, and then instruct each user to copy that file to devtargets.rb (which is on the .gitignore list). For example, CakePHP does the same for its database configuration file which naturally changes from machine to machine.