title: FactoryGirl Inheritance attribute already defined
body: <p>Alright guys. How does this even make sense? The two nested factories (which is considered an inheritance by FactoryGirl) should not conflict with each other. What the heck is going on? Either it's not inheritance or it is. I don't know why they'd call it inheritance if it weren't. Am I just doing something wrong? (Notice <code>f.account_type</code>)</p>
  
  <p>Take a look at the factory definition below.</p>
  
  <pre><code>factory :partner do |f|
    f.company_name { Faker::Company.name }
    f.username { Faker::Internet.user_name }
    f.password { Faker::Internet.password }
    f.password_confirmation { password }
    f.pid { Faker::Lorem.word }
  
    f.association :primary_contact
  
    # Inherited
    factory :business_partner do
      f.account_type "business"
      f.tax_id { Faker::Company.duns_number }
    end
  
    # Inherited
    factory :personal_partner do
      f.account_type "personal"
      f.ssn { Faker::Company.duns_number }
    end
  
  end
  </code></pre>
  
  <p>When I run my tests, I get this error.</p>
  
  <pre><code>Failure/Error: partner = FactoryGirl.create(:business_partner)
    FactoryGirl::AttributeDefinitionError:
      Attribute already defined: account_type
  </code></pre>
  
  <p>And just for completeness, my spec.</p>
  
  <pre><code># spec/models/partner.rb
  require 'spec_helper'
  require 'pp'
  
  describe Partner do
  
    it "has a valid factory" do
      partner = FactoryGirl.create(:business_partner)
      partner.should be_valid
      puts partner
    end
  
    it "is invalid without a firstname" do
  #    FactoryGirl.build(:partner_contact, first_name: nil).should_not be_valid
    end
  
    it "is invalid without a lastname" do
  #    FactoryGirl.build(:partner_contact, last_name: nil).should_not be_valid
    end
  
    it "is invalid without an email address" do
  #    FactoryGirl.build(:partner_contact, email: nil).should_not be_valid
    end
  
    #it "returns a contact's fullname as a string"
  
  end
  </code></pre>