Gem needs to append column to passed model

Question

I cannot find out how to have my gem append a column to an existing model/table. My gem needs to check the created_at attribute of a model, and based on time passed, set an active column from true to false. I'm assuming that, upon install, it will end up needing a

$ rails {gem_name}:install

type call from the terminal to append the active column to the model's table. I don't think that an engine is the way to go because I'm not creating any models in the gem, and the only migration I need is to alter an existing model.

Any links, tutorials or advice will be greatly appreciated.

Answer 1

I finally found the answer to this issue after posting the question again with a little more information and a little more background.

Please see it here

Basically following the devise gem code base and parsing out what I did and didn't need

Answer 2

It seem you are a beginner. What do you think reading the fine manual on

 http://guides.rubyonrails.org/getting_started.html