投稿者情報追加（#17） (#18)

#17

#17

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #18

db/models.py

@@ -81,6 +81,7 @@ class User (Model):
 class Video (Model):
     id:             int
     code:           str
+    user_id:        int | None
     title:          str
     description:    str
     uploaded_at:    datetime
@@ -88,6 +89,14 @@ class Video (Model):
 
     __timestamps__ = False
 
+    @property
+    def user (
+            self,
+    ) -> User | None:
+        if self.user_id is None:
+            return None
+        return self.belongs_to (User)
+
     @property
     def video_histories (
             self,