Rename BackendGroup to Environment.
Following @kierdavis's suggestions in #5 (closed), I think that a more appropriate name for BackendGroup would be Environment.
Note, this PR is currently set to merge into the branch for #10
Following @kierdavis's suggestions in #5 (closed), I think that a more appropriate name for BackendGroup would be Environment.
Note, this PR is currently set to merge into the branch for #10