Password reset

1) add PasswordResetController
2) add views for PasswordResetController
3) add specs for PasswordResetController
4) add code for PasswordResetController
5) add validation on password length

Please approve.
Actually, I do that on purpose, and it is because password_reset is not a model-backed. Chris reached us to use  resources for REST style model backed controllers while he likes single routes in case of non-model backed controllers. And I was sticking to this convention. So its most likely an aesthetic feature.