Force ordering by created at
Force ordering by created at

Sometimes my listing as jsonstest would fail for no obvious reason.
Turns out DataMappers `all` method doesn't enforce ordering by default.

We're telling data mapper to order results by the `created_at` field of
the `Overheard` model; and to put the largest (i.e. most recent) at the
top. [Documentation](http://datamapper.org/docs/find.html) (Search for
"Specify the order")

chrisswk/overheard-server,codeunion/overheard-server,mjgold/overheard-server,chrisswk/overheard-server