old_contents: import packages
  import util
  
  packages.try_install('git')
  util.create_symlink('./gitconfig', '~/.gitconfig')
  util.create_symlink('./gitignore', '~/.gitignore')
  
new_contents: import packages
  import util
  
  packages.try_install('git')
  packages.try_install('git-extras-git')
  util.create_symlink('./gitconfig', '~/.gitconfig')
  util.create_symlink('./gitignore', '~/.gitignore')
  
subject: add git extras