Please check out how to turn on the OSX Server Xcode service at the following link:
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Important Conceptual Notes:
When you setup a new project and you are offered a server this refers to an OSX Server only (not github or any non-OSX external server):
So basically just make sure the OSX Xcode service is ON or restart your 10.9+ OSX server if possible...
NB: If what you want to do is to push your repository to github.com or code.google.com please see the following links for instructions on getting this to run in Terminal. Once the link between the remote repository and your local directory then Xcode will be able to push updates to your remote repositories (this will be available as a checkbox when you commit your project).