git-railed is a simple script that creates a new rails app, initializes a new git repository, moving the db config and setting up the ignores for you.
As a gem:
sudo gem install ambethia-git-railed -s http://gems.github.com git-railed my_app_name
As a sake task:
sake -i http://github.com/ambethia/git-railed/tree/master/lib/git-railed.rake?raw=true sake git-railed APP=my_app_name
Until I can figure out how (if it's even possible) to change the working directory of the parent process, you'll have to cd my_app_name yourself after running git-railed. Boo.