codigo Ruby on Rails (para el que ya sabe)

Generar:

$ rails generate model User name:string email:string
$ rails generate controller StaticPages home help


Eliminar:

$ rails destroy model User


Actualizar base de datos:

$ bundle exec rake db:migrate

Rollback:
$ bundle exec rake db:rollback
$ bundle exec rake db:migrate VERSION=0 (rollback a la version 0)