Should I use class method or instance method, and why?

Question

In my Rails app, when creating a business I have a form that has the following field:

   <%= check_box_tag(:default_company) %> 
   <%= label_tag(:defau         


        

Answer 1

I would actually make set_default_company an instance method on User. A User has a default Company; why should a Company need to what users it is default for?

class User
    def set_default_company(company)
        exists = DefaultCompany.find(id)
        if exists
            exists.update_attributes(company: company)
        else  
            DefaultCompany.create(company: company, user: self)
         end
     end
 end