Create a global config file when sgit config --global is executed

[ksdhans]

When trying to set a global user.name/email, sgit returns:
libgit error (7): Cannot set value for 'user.name' when no config files exist

I have no idea how to create such a config file or where to put it. So, it would be very useful if it automatically created the config file for global settings.

[sba1]

The file will be created now if doesn't exist. Thanks for the report!