2.4 Guestbook FormView

- Limit greeting messgae max=10 letters
- Using django FormView to validate post data, and auto show invalid
fields
2.4 Guestbook FormView

redirect to guestbook
add Form Switch guestbook

add Form Switch guestbook
Fix comment

- remove unused method in form Switch
- use one form to display error
Change app name
Merge pull request #5 from nhathv/feature/formview

Merged pull request #5 Feature/formview