Lets add some ui

Known issues:
- The way I'm redirecting from index to search is hella-ghetto. What's the proper Rails way to do this?
- Image size is wrong on the welcome index page. We need a migration to fix this, will do that in a separate PR.
- v1 UI. Still lots of little things I could do to make it prettier, still lots of room to add features, still time to overhaul this if everyone hates it.

Here's how this looks now:
![welcome](https://cloud.githubusercontent.com/assets/590055/3781467/8b27c5a6-1996-11e4-8ee0-27bd6ff7f0ff.png)
![search](https://cloud.githubusercontent.com/assets/590055/3781468/8b28246a-1996-11e4-89b0-0f059b54b2f1.png)
haha it's a pretty brutal interaction. You click the button, the page stays open awkwardly while the DB stuff all runs, then when rails gives us all the data, we switch the page. At the very least it needs a load spinner or something, but I think we need to do this differently.