PerfectMemory/mongoid-multitenancy — pull request #7 by neckhair (2013-09-24 07:19:07+00:00)
Title: _type Attribute is now saved on inherited models.

Scenario:
```ruby
class Animal
tenant :account
field :name, type: String
end

class Cat < Animal
field :age, type: Integer
end
```

When saving a ```Cat``` model, its ```_type```-attribute was not saved to mongodb. So when calling ```Animal.last``` the resulting object was of type ```Animal``` instead of ```Cat```.

Solved this by adding a call to ```super``` in ```define_singleton_method``` in the ```tenant```-Method.