Add jazz_hands

`rails console` の時に 出力を整形してくれるgemの追加

##before
![screen shot 2014-03-01 at 6 51 36 am](https://f.cloud.github.com/assets/823185/2298800/8be2f094-a0c2-11e3-8251-53c7cc5a6782.png)

##after
![screen shot 2014-03-01 at 6 40 04 am](https://f.cloud.github.com/assets/823185/2298675/f229019c-a0c0-11e3-89a4-18f1ec549108.png)