add relationship

src/classes/relation.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from enum import Enum
+
+
+class Relation(Enum):
+    KINSHIP = "kinship"            # 亲子/亲属
+    LOVERS = "lovers"              # 情侣/道侣
+    MASTER_APPRENTICE = "mentorship"  # 师徒
+    FRIEND = "friend"              # 朋友
+    ENEMY = "enemy"                # 仇人
+
+    def __str__(self) -> str:
+        return relation_strs.get(self, self.value)
+
+
+relation_strs = {
+    Relation.KINSHIP: "亲属",
+    Relation.LOVERS: "情侣",
+    Relation.MASTER_APPRENTICE: "师徒",
+    Relation.FRIEND: "朋友",
+    Relation.ENEMY: "仇人",
+}
+
+