update new model: Switch

- add state field
- add get/setstate method

Signed-off-by: Amos Kong <kongjianjun@gmail.com>
add new model to INSTALLED_APPS and syncdb

 # python manage.py syncdb

Signed-off-by: Amos Kong <kongjianjun@gmail.com>
add README

Signed-off-by: Amos Kong <kongjianjun@gmail.com>