rails3 bigint primary key

Question

I would like to create a bigint (or string or whatever that is not int) typed primary key field under Rails 3.

I have a given

Answer 1

For those of you who came here (like I did) in an effort to figure out how to make a custom id column that uses bigint instead of int, what I didn't realize is that for Rails 5.1 and above, bigint is the default type for id

https://github.com/rails/rails/pull/26266