SQLite migration bug?
I can confirm the weird behavior with the testcase above and on my code too. In my case the models are similar: a Feed model and an Entry model, with the latter having a FK to Feed. 

On my machine it gives this error:

> peewee.OperationalError: table page__tmp__ has no column named FOREIGN

I'm using:

```
Underworld:$ python
Python 2.7.6 (v2.7.6:3a1db0d2747e, Nov 10 2013, 00:42:54) 
>>> import sqlite3 as s
>>> s.version
'2.6.0'
>>> s.sqlite_version
'3.7.13'
```
 Replicated this in a test-case, working up a fix.

``` python
class User(BaseModel):
    id = peewee.CharField(primary_key=True, max_length=20)

class Page(BaseModel):
    id = peewee.PrimaryKeyField()
    name = peewee.TextField(unique=True, null=True)
    user = peewee.ForeignKeyField(User, null=True, related_name='pages')
```

Migration Script:

``` python
from playhouse import migrate

my_db = migrate.SqliteDatabase('database')
migrator = migrate.SqliteMigrator(my_db)

with my_db.transaction():
    migrate.migrate(
        migrator.rename_column('page', 'name', 'title')
    )
```
