Query experiment


    $ curl "localhost:8080/increment?expId=999&armId=AAA&offers=1"
    OK
    $ curl "localhost:8080/increment?expId=999&armId=BBB&offers=1"
    OK
    $ curl "localhost:8080/increment?expId=999&armId=BBB&rewards=1"
    OK
    $ curl "localhost:8080/query?expId=999"
    {"errors":[],"results":[{"rewards":1,"offers":1,"armId":"BBB"},{"rewards":0,"offers":1,"armId":"AAA"}]}

Do you want to use a default storage mechanism other than prevayler? I'm proposing it because it looks fast http://databen.ch/ Prevayler stores it's data in a series of data 'journals' that look like:

```
0000000000000000001.journal
0000000000000000002.journal
```
We could rename the directory to `data` but the data stored as shown above. Is this cool?