rails/rails — pull request #7419 by releu (2012-08-22 11:35:07+00:00)
Title: Ensure valid migration filename on generating migration

```bash
rails g migration add_statistic_updated_at:datetime

create db/migrate/20120822103649_add_statistic_updated_at:datetime.rb

rake db:migrate

llegal name for migration file: ...db/migrate/20120822103649_add_statistic_updated_at:datetime.rb
(only lower case letters, numbers, and '_' allowed)
```