ArrayField of ForeignKeyFields, is it possible?
I wouldn't call that trickery, I'd call it ... well, nevermind.

Just use an actual junction table. Play to the strengths of your relational database. Sorry to resurrect an old thread, but if anyone (like me) is looking for a similar thing: have a look at the [ManyToManyField](http://docs.peewee-orm.com/en/latest/peewee/api.html#ManyToManyField)
Hi!
I'm working with postgresql and peewee 3.7.1 and trying to initialize model's field as an array of ForeignKeyFields this way:

```python
PreviousTasks = ArrayField(ForeignKeyField, {'model': 'self', 'column_name': 'previous_tasks', 'field': 'ID', 'backref': 'TaskPreviousTasks'})
```
Docs say ArrayField argument field_class gets "a subclass of Field" so this should be possible theoretically. But I'm getting this error:
```python
  File "/opt/app/include/models/tickets.py", line 176, in <module>
    class Task(ModelBase):
  File "/opt/app/include/models/tickets.py", line 191, in Task
    PreviousTasks = ArrayField(ForeignKeyField, {'model': 'self', 'column_name': 'previous_tasks', 'field': 'ID', 'backref': 'TaskPreviousTasks'})
  File "/usr/local/lib/python3.6/site-packages/playhouse/postgres_ext.py", line 155, in __init__
    self.field_type = self.__field.field_type
  File "/usr/local/lib/python3.6/site-packages/peewee.py", line 4552, in __getattr__
    if attr in self.rel_model._meta.fields:
AttributeError: 'str' object has no attribute '_meta'
```
Is there any way to do this kind of trickery or should I use PreviousTasks as an array of integers and fetch referenced models manually?