Add Alembic support sqlalchemy 2.0

[Mac3g0d]

copy
#20
from @abdalazizrashid

with passed codestyle but not fully tested
for base case like simple table with strings, ints, and uuidv7 as primary_key its works fine

[vgvoleg]

Hi! have you followed instructions described here? alembic works fine with them
https://github.com/ydb-platform/ydb-sqlalchemy/tree/main/examples/alembic

[Mac3g0d]

Hi! have you followed instructions described here? alembic works fine with them https://github.com/ydb-platform/ydb-sqlalchemy/tree/main/examples/alembic

Hi @vgvoleg!
Sorry, I made a mistake.
The problem is as follows: if you specify a naming convention in the metadata that you set in the Base class and then pass it to other classes, SQLAlchemy thinks that the field is a primary key and tries to generate a string like
PRIMARY KEY ...

Here is an example of the base class code that breaks the YQL dialect:

convention = {
    "ix": "ix_%(column_0_label)s",
    "uq": "uq_%(table_name)s_%(column_0_name)s",
    "ck": "ck_%(table_name)s_%(constraint_name)s",
    "fk": "fk_%(table_name)s_%(column_0_name)s_%(referred_table_name)s",
    "pk": "pk_%(table_name)s",
}

class Base(DeclarativeBase):
    __abstract__ = True

    metadata = MetaData(naming_convention=convention)

I solved my problem, I will cancel the PR, but probably this case should be recorded as a bug.