Added peewee-aio to Database Drivers

[klen]

What is this project?

Peewee-AIO makes Peewee ORM really async (and typing support). All peewee methods are implemented.

So we have another nice async ORM library here

    import peewee
    from peewee_aio import Manager, AIOModel, fields

    manager = Manager('aiosqlite:///:memory:')

    @manager.register
    class Role(AIOModel):
        # Pay attention that we are using fields from Peewee-AIO for better typing support
        id = fields.AutoField()
        name = fields.CharField()

    @manager.register
    class User(AIOModel):

        # Pay attention that we are using fields from Peewee-AIO for better typing support
        id = fields.AutoField()
        name = fields.CharField()
        role = fields.ForeignKeyField(Role)

    async def handler():

        # Initialize the database's pool (optional)
        async with manager:

            # Acquire a connection
            async with manager.connection():

                # Create the tables in database
                await Role.create_table()
                await User.create_table()

                # Create a record
                role = await Role.create(name='user')
                assert role
                assert role.id  # role.id contains correct string type
                user = await User.create(name="Andrey", role=role)
                assert user
                assert user.id
                role = await user.role  # Load role from DB using the foreign key
                assert role  # role has a correct Role Type

                # Iterate through records
                async for user in User.select(User, Role).join(Role):
                    assert user  # user has a corrent User Type
                    assert user.id
                    role = await user.role  # No DB query here, because the fk is preloaded

                # Change records
                user.name = "Dmitry"
                await user.save()

                # Update records
                await User.update({"name": "Anonimous"}).where(User.id == user.id)

                # Delete records
                await User.delete().where(User.id == user.id)

                # Drop the tables in database
                await User.drop_table()
                await Role.drop_table()

Why is it awesome?

There are no so many async ORM are available and Peewee has a quite nice syntax so it's maybe helpful.
There is already peewee-async on the list, but the library doesn't change Peewee behaviour and you need write a lot of more code to use it. Peewee-AIO makes Peewee models really async and users are able to use similar Peewee syntax but in async way.