can't create a model that inherits from "dict"
Ah, thanks -- I will clarify that if statement!
 aren't there a few other places where a similar fix would be needed ?
 Curious, how would you use peewee to inherit from dict, and then use it as a dict?

I tried farialima's model but standard dict features didn't work.

I have a need to use the DB as a dict, and am not seeing it :)
 http://peewee.readthedocs.org/en/latest/peewee/playhouse.html#key-value-store

the following code:

```
class MyModel(Model, dict):
    class Meta:
        database = SqliteDatabase(':memory:')
    id = CharField(primary_key=True)
o = MyModel()
print repr(o.id)
```

will show:
`<peewee.CharField object at 0x1079ca5d0>`
instead of the expected:
`None`

The problem is that o is an empty dictionary "{}", which is a boolean false.
Workaround is to ensure that the object never evaluate to false, eg.:

```
class MyModel(Model, dict):
    def __init__(self, *k, **v):
        super(MyModel, self).__init__(*k, **v)
        self['default'] = ''                                                                                                                                                   
    class Meta:
        database = SqliteDatabase(':memory:')
    id = CharField(primary_key=True)
```

The correct solution is to replace 

```
class FieldDescriptor
    (...)
    def __get__(self, instance, instance_type=None):
    (...)
        if instance:
            return instance._data.get(self.att_name)
```

with:

```
       if instance != None:
           return instance._data.get(self.att_name)
```

and possibly in a few other places (I haven't checked).

It took me time to debug it -- the fact that many objects evaluate to boolean False is really a pain in Python (the only one ?) 
Thanks for this great library, in any case.
