`parent_id` as zero

[nolleto]

Hi, in my current project I'm trying to add this gem and work very well. I just found something annoying that in our parent_id column (that in this project is parent_widget_id) is a required integer

create_table "widgets", id: :serial, force: :cascade do |t|
  t.integer "parent_widget_id", default: 0
  ...
end

So, I was wondering if it is possible to set the root node with 0 value instead of nil?

Just some extra information, this is a really huge project and it's a little hard to find all parent_widget_id logic where is treating the root as 0 then, update the table to convert it to a nullable value to accept nil can lead to some headaches. 😓

[seuros]

having 0 in the field break database integrity. use foreign keys to avoid having wrong structure.