enhancement to simplify the BaseModel boilerplate code
ps: i've seen this pattern from [sqla-wrapper](https://sqla-wrapper.scaletti.dev/sqlalchemy-wrapper/). this library might be helpful as well. another enhancement:

```python
# /usr/local/lib/python3.9/dist-packages/peewee.py:3420

#   def create_tables(self, models, bind=True,**options):
#       for model in sort_models(models):
#          if bind:
#              model.bind(self)
#          model.create_table(**options)
class User2(Model):
    username = CharField(unique=True)

db.create_tables([User2])

``` I'm going to pass on the `create_tables()` but have merged the `Model` property helper.
i wrote some code for simplification:

```python

from peewee import *

# some patch on /usr/local/lib/python3.9/dist-packages/peewee.py:3142

# @property
# def Model(self): # this is interesting. does it work as expected?
#     class BaseModel(Model):
#         class Meta:
#             database = self
#     return BaseModel

db = SqliteDatabase('my_database.db')
class User(db.Model):
    username = CharField(unique=True)

```