how to add current project path to alembic env.py for module dynamically import

from __future__ import with_statement

from alembic import context

from sqlalchemy import engine_from_config, pool

from logging.config import fileConfig

import sys, os

base_alembic_dir = os.path.abspath(os.path.dirname(__file__))

base_project_dir = os.path.dirname(base_alembic_dir)

sys.path.append(base_project_dir)

# this is the Alembic Config object, which provides

# access to the values within the .ini file in use.

config = context.config

# Interpret the config file for Python logging.

# This line sets up loggers basically.

fileConfig(config.config_file_name)

# add your model's MetaData object here

# for 'autogenerate' support

# from myapp import mymodel

# target_metadata = mymodel.Base.metadata

target_metadata = None

# other values from the config, defined by the needs of env.py,

# can be acquired:

# my_important_option = config.get_main_option("my_important_option")

# ... etc.