code: def setup(app):
      
      app.info('Initializing GitHub plugin')
      app.add_role('ghissue', ghissue_role)
      app.add_role('ghpull', ghissue_role)
      app.add_role('ghuser', ghuser_role)
      app.add_role('ghcommit', ghcommit_role)
      app.add_config_value('github_project_url', None, 'env')
      return
docs: Install the plugin.
      
      :param app: Sphinx application context.