feat: add common model

src/arcaea_offline/models/common.py

@@ -0,0 +1,18 @@
+from sqlalchemy import TEXT
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
+
+__all__ = [
+    "CommonBase",
+    "Property",
+]
+
+
+class CommonBase(DeclarativeBase):
+    pass
+
+
+class Property(CommonBase):
+    __tablename__ = "property"
+
+    id: Mapped[str] = mapped_column(TEXT(), primary_key=True)
+    value: Mapped[str] = mapped_column(TEXT())