refractor structure project and add user endpoint

backend/app/migration/env.py

@@ -7,9 +7,8 @@ from sqlalchemy.ext.asyncio import async_engine_from_config
 
 from alembic import context
 
-from app.users.models import UserModel
-from app.database import Base
-from app.config import settings
+from app.core.database import Base
+from app.core.config import settings
 
 # this is the Alembic Config object, which provides
 # access to the values within the .ini file in use.