Update README with required env variables.
Update README with required env variables.

xzzy/statdev,brendanc-dpaw/statdev,ropable/statdev,parksandwildlife/statdev,xzzy/statdev,xzzy/statdev,ropable/statdev,parksandwildlife/statdev,brendanc-dpaw/statdev,parksandwildlife/statdev