Users submit and vote prompts

Prompts/index:
![selection_032](https://cloud.githubusercontent.com/assets/8248100/5235881/c45aa632-77e6-11e4-9282-3a9f41d29770.png)

Prompts show page:
![selection_033](https://cloud.githubusercontent.com/assets/8248100/5235883/db53f546-77e6-11e4-9f98-634157d328ac.png)