add school field to guest

apps/activity/models.py

@@ -247,6 +247,11 @@ class Guest(models.Model):
         verbose_name=_("first name"),
     )
 
+    school = models.CharField(
+        max_length=255,
+        verbose_name=_("school"),
+    )
+
     inviter = models.ForeignKey(
         NoteUser,
         on_delete=models.PROTECT,