Custom primary key ID for Avram

custom_id.cr

alias CustomID = String

module Avram::Migrator::Columns::PrimaryKeys
  class CustomIDPrimaryKey < Avram::Migrator::Columns::PrimaryKeys::Base
    def initialize(@name)
    end

    def column_type : String
      "character varying(18)"
    end
  end
end

module Avram::Migrator::Columns
  class CustomIDColumn < Avram::Migrator::Columns::Base
    @default : String? = nil

    def initialize(@name, @nilable, @default)
    end

    def column_type : String
      "character varying(18)"
    end
  end
end

save_user.cr

class SaveUser < User::SaveOperation
  include CustomIDGenerator
  before_save do
    id.value ||= generate_new_custom_id
  end
end

user.cr

class User < BaseModel
  skip_default_columns
  
  table do
    primary_key id : CustomID
  end
end