initialize last_seen_notif_id in db.py

db.py

@@ -41,6 +41,9 @@ cursor.execute("""
         )
     """)
 
+# Initialize essential config key
+cursor.execute('INSERT INTO config VALUES ("last_seen_notif_id", 0)')
+
 """ # Insert example characters into the database if they don't already exist
 characters = [
     ('Murakami-san', 1, 0.35),