text: # coding=utf-8
  class MasterSlaveRouter(object):
      """
      A router to control all database operations on models in the
      auth application.
      """
      def db_for_read(self, model, **hints):
          """
          Attempts to read auth models go to auth_db.
          """
          return 'slave'
  
      def db_for_write(self, model, **hints):
          """
          Attempts to write auth models go to auth_db.
          """
          return 'default'
  
      def allow_relation(self, obj1, obj2, **hints):
          """
          Allow relations if a model in the auth app is involved.
          """
          return True
  
      def allow_migrate(self, db, app_label, model=None, **hints):
          """
          Make sure the auth app only appears in the 'auth_db'
          database.
          """
          return True