データによっては変換エラーがでる？

```
get_tweet.rb:141:in `[]': can't convert String into Integer (TypeError)
        from get_tweet.rb:141:in `block in <main>'
        from get_tweet.rb:137:in `reverse_each'
        from get_tweet.rb:137:in `<main>'
make: *** [run] Error 1
```
