Added more motivation for pods and labels.

And put them into a subsection together.
On Wed, Jun 18, 2014 at 10:43 AM, Joe Beda <notifications@github.com> wrote:

> Suggest s/stage/stack/. There is no well accepted terminology here but
> stack is probably the closest.
>
>
> I've never heard "stack" used in that context. It makes me think "LAMP
stack".

The term used at Dockercon was "environment", which is also the term that
pops up most when I Google search "development test production". How about
that?