ENV fixes and upgrade plan by default.

The S3 key was the wrong one cause S3 to not be setup correctly.
In addition I had the wrong ENV for MANDRILL causing e-mail to not
be configured correctly when using mandrill.

Finally I found the free redis plan unworkable. There were not enough
connections allowed. Perhaps if we can reduce the number of connections
that Discourse uses we could use the free plan. But for now you must
at least pony up $10/month.