class GitHubPages::Configuration

def set!(site)

Should be called by #set to protect against multiple processings.
Set the site's configuration with all the proper defaults and overrides. 
def set!(site)
  config = effective_config(site.config)
  # Assign everything to the site
  site.instance_variable_set :@config, config
  # Ensure all
  CONFIGS_WITH_METHODS.each do |opt|
    site.public_send("#{opt}=", site.config[opt])
  end
  # While Configuration renamed the gems key to plugins, Site retained
  # backwards compatability and must be set manually
  site.gems = site.config["plugins"]
end