Thanks Javier and what about ID (PK) fields? Need to be specified too or Rails is smart enough to get them from tables?
To be clear, the instructions that Javier gave you are to create a new table and model to match, not to introspect an existing database table and infer a model from it. This instruction is precisely how you create a new model when starting a green-field Rails application.
To answer your follow up question, yes, Rails will add id, created_at and updated_at columns (int-11, datetime, datetime) automagically. You can certainly follow these steps (and be sure to issue the --skip-migrations flag at the end so you don't end up with a redundant migration file) but I don't think this is actually the answer you were looking for. I don't have one for you either, sorry, but I didn't want you to go down this path and get confused when it didn't do what you asked for.