roster: extract to a separate module

pqcli/roster.py

@@ -0,0 +1,23 @@
+import pickle
+import typing as T
+from pathlib import Path
+
+from pqcli.mechanic import Player
+
+
+class Roster:
+    def __init__(self) -> None:
+        self.players: T.List[Player] = []
+
+    def add_player(self, player: Player) -> None:
+        self.players.append(player)
+
+    @staticmethod
+    def load(path: Path) -> "Roster":
+        if path.exists():
+            return pickle.loads(path.read_bytes())
+        return Roster()
+
+    def save(self, path: Path) -> None:
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_bytes(pickle.dumps(self))