refactor: remove Alembic migrations and Discord integration

tgbot/database/migration_runner.py

@@ -12,13 +12,11 @@ from tgbot.database.core import database_url
 
 PROJECT_ROOT = Path(__file__).resolve().parents[2]
 ALEMBIC_INI = PROJECT_ROOT / "alembic.ini"
-MIGRATIONS_DIR = PROJECT_ROOT / "migrations"
 
 
 # Сбор Alembic-конфига от корня проекта
 def get_alembic_config(url: str = database_url) -> Config:
     config = Config(str(ALEMBIC_INI))
-    config.set_main_option("script_location", str(MIGRATIONS_DIR))
     config.set_main_option("sqlalchemy.url", url)
 
     return config