Fix preferences for new users

src/invidious/helpers.cr

@@ -766,6 +766,7 @@ def get_user(sid, client, headers, db, refresh = true)
     if refresh && Time.now - user.updated > 1.minute
       user = fetch_user(sid, client, headers, db)
       user_array = user.to_a
+      user_array[5] = user_array[5].to_json
       args = arg_array(user_array)
 
       db.exec("INSERT INTO users VALUES (#{args}) \