Run With Unicorn, For Great Justice!

Much better throughput on the 1 Heroku dyno before having to pay for more.

Siege output, running 5 concurrent requests locally:

**rails server**
```
Transactions:		         179 hits
Availability:		      100.00 %
Elapsed time:		       19.31 secs
Data transferred:	        2.93 MB
Response time:		        0.53 secs
Transaction rate:	        9.27 trans/sec
Throughput:		        0.15 MB/sec
Concurrency:		        4.92
Successful transactions:         179
Failed transactions:	           0
Longest transaction:	        1.51
Shortest transaction:	        0.22
```

**unicorn** (twice the throughput, roughly)
```
Transactions:		         374 hits
Availability:		      100.00 %
Elapsed time:		       19.75 secs
Data transferred:	        6.13 MB
Response time:		        0.26 secs
Transaction rate:	       18.94 trans/sec
Throughput:		        0.31 MB/sec
Concurrency:		        4.91
Successful transactions:         374
Failed transactions:	           0
Longest transaction:	        1.02
Shortest transaction:	        0.16
```