No use of flashing a message if the user is redirected to the login page.
Code layout in the form
By re-creating the form after validation, the errors get lost and thus not displayed to the user
Color the information message in green

fixes https://github.com/fedora-infra/nuancier/issues/20
Be consistent about the css class to use for error message

The default class 'message' is singular so use the singular class 'error' for error messages
Fix the name of the 'error' and 'warning' css class to use a consistent singular form
Fix the css class from warnings to warning
Flash the information message only when an election was updated w/o problems
Check the method of the request and pre-fill the form when needed