Add sqlalchemy and alembic

mybot/database/__init__.py

@@ -0,0 +1,15 @@
+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase
+
+from ..config import Config
+
+
+def get_engine(config: Config):
+    engine = create_engine(config.DB_URL,
+                           pool_recycle=3600,
+                           pool_pre_ping=True)
+    return engine
+
+
+class Base (DeclarativeBase):
+    pass

mybot/database/models.py

@@ -0,0 +1,12 @@
+from sqlalchemy import BIGINT, String
+from sqlalchemy.orm import Mapped, mapped_column
+
+from . import Base
+
+
+class User (Base):
+    __tablename__ = "user"
+
+    id: Mapped[int] = mapped_column(BIGINT, primary_key=True, unique=True, autoincrement=False)
+    username: Mapped[int] = mapped_column(String(32), unique=True, nullable=True)
+    # additional fields go here