Introduce core library model

serato_doctor/models/crate.py

@@ -0,0 +1,13 @@
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Tuple
+
+from serato_doctor.models.reference import TrackReference
+
+
+@dataclass(frozen=True)
+class Crate:
+    """A Serato crate and the track references parsed from it."""
+
+    path: Path
+    references: Tuple[TrackReference, ...]