Spike add password change decoration for authentication token renewal

**As a** developer 
**In order to** get an insight of which way could lead to effectively decoration the `Devise::PasswordsController#update` action 
**And** to be able to decide which is the better way to write the [corresponding RSpec example][example]
**I want** to explore some of the possible implementations 

  [example]: https://github.com/gonzalo-bulnes/simple_token_authentication/blob/9c7c9f9a193fffc6566234fca7f890262eea561b/features/password_change_provokes_the_token_authentication_reset.feature#L57-L73