refs #90 特定ユーザのツイートを取り込まないようにしたい

Unused method argument - `tweet`. If it's necessary, use `_` or `_tweet` as an argument name to indicate that it won't be used. You can also write as `is_excluded_twitter_user?(*)` if you want the method to accept any arguments but don't care about them.<br>Inconsistent indentation detected.<br>Rename `is_excluded_twitter_user?` to `excluded_twitter_user?`.