Add "Web UI" to inspecting the queue

I put together a [gem](https://github.com/statianzo/que-web) for a web interface to Que. Currently, it will give you a breakdown of running, scheduled, and failing jobs. Deleting and scheduling immediately works. It also gives you visibility into the `last_error` stack traces.

![failing](https://cloud.githubusercontent.com/assets/57737/5074633/8121289c-6e49-11e4-9e6b-0e1ef0125249.png)
![job](https://cloud.githubusercontent.com/assets/57737/5074635/8121bcb2-6e49-11e4-9a6f-816c3e40a7b4.png)
![scheduled](https://cloud.githubusercontent.com/assets/57737/5074634/8121f5a6-6e49-11e4-89ff-d7f525874590.png)