Orphan list bug

PT story: https://www.pivotaltracker.com/story/show/79488584

- Fixed all three bugs
- Introduced features to test the fix
- Introduced specs to ensure an orphan list can only be created for an active partner
- Introduced orphan_list factory
I'd rewrite this for clarity as

```ruby
active_status = build_stubbed :status, name: 'Active', code: 1 # can't wait for those fixtures!
active_partner = build_stubbed :partner, status: active_status
expect(build_stubbed :orphan_list, partner: active_partner).to be_valid
```

In fact, what about

```ruby
describe OrphanList, type: :model do

  it { is_expected.to validate_presence_of :partner }
  it { is_expected.to validate_presence_of :orphan_count }
  it { is_expected.to validate_presence_of :spreadsheet }

  let(:active_status) { build_stubbed :status, name: 'Active', code: 1 }      # Fixtures!!!!
  let(:inactive_status) { build_stubbed :status, name: 'Inactive', code: 2 }  # @%^&!!!
  let(:active_partner) { build_stubbed :partner, status: active_status }
  let(:inactive_partner) { build_stubbed :partner, status: inactive_status }

  it 'should have a valid factory & belong to an active partner' do
    expect(build_stubbed :orphan_list, partner: active_partner).to be_valid
  end

  it 'should not be valid with an inactive partner' do
    expect(build_stubbed :orphan_list, partner: inactive_partner).not_to be_valid
  end
end
```