postgresql: invalid last insert id when setting id manually
> may be we must use "INSERT **\* RETURNING id"?

That is a postgres feature, unfortunately it won't work for Sqlite or MySQL... Setting an auto-incrementing ID manually is frowned on, but if you are bulk-loading data or for some reason need to control the ids, see these docs for some tips:

http://peewee.readthedocs.org/en/latest/peewee/cookbook.html#bulk-loading-data-or-manually-specifying-primary-keys

```
In [17]: cat = Category.create(name='a')

In [18]: cat.id
Out[18]: 1L

In [19]: cat = Category.create(name='b')

In [21]: cat.id
Out[21]: 2L

In [22]: cat = Category.create(name='c', id=100)

In [23]: cat.id
Out[23]: 2L

=========

select * from categories;
 id  | parent_id | name 
-----+-----------+------
   1 |           | a
   2 |           | b
 100 |           | c
(3 rows)

```

may be we must use "INSERT **\* RETURNING id"?
