reduce env vars.

[BrianHGrant]

This commit would reduce the number of env vars, taking out the "Development" vs. "Production". Updated the README.

This is partially in response to:
#13 (comment)

If we merge, will mean that you will need to change the .env variables when going from dev to prod build, when running locally.

[MikeTheCanuck]

This reads well and looks simpler. If I wasn’t on a plane I’d test the sample app to be sure these changes didn’t break it; if other reviewers are confident this will work then let’s get this sucker merged.

Thanks everyone for tolerating my fixations.

[znmeb]

Ship it!!