Has_many :through and has_one :through associations

Hello,

First I’m using Rails 3.1 from the 3-1-stable branch updated an hour
ago.

I’m developing an application where I have 3 essential models User,
Company and Job, Here’s the relevant part of the models:

class User < ActiveRecord::Base
has_many :companies_users, class_name: “CompaniesUsers”
has_many :companies, :through => :companies_users, :source => :company
end

class Company < ActiveRecord::Base
has_many :companies_users, class_name: “CompaniesUsers”
has_many :employees, :through => :companies_users, :source => :user
has_many :jobs, :dependent => :destroy
end

class Job < ActiveRecord::Base
belongs_to :company, :counter_cache => true
end

class CompaniesUsers < ActiveRecord::Base
belongs_to :company
belongs_to :user
end

The code works just fine, but I have been wondering if it’s possible to:

I want to link a job with an employer, so think of this scenario: A user
John who’s an employee at Example, he posted the job Rails Developer, so
I want to access @job.employer and it should get me back the user John,
in other words:

@user = User.find_by_name(‘john’)
@job = Job.find(1)
@job.employer == @user #=> true

So I thought of two possible solutions

First solution

class Job
has_one :employer, :through => :employers
end

class User
has_many :jobs, :through => :employers
end

class Employer
belongs_to :job
belongs_to :user
end

Second solution

class Job
has_one :employer, :class_name => “User”
end

class User
belongs_to :job
end

Which route should I go? Is my code right ?

I have another question, how to get rid of the class_name =>
“CompaniesUsers” option passed to has_many, should the class be Singular
or Plural ? Should I rename it to something like Employees ?

P.S: I posted the same question to Stackoverflow