Better explanation for https://github.com/18F/domain-scan#setting-tool-paths

[ArcTanSusan]

The current instructions aren't clear about where/how to set the environmental variables required for localdev.

[konklone]

No? I generally feel like environment variables are so standard in Unix environments that I'm comfortable letting people set that in whatever way works for them.

I use autoenv, would adding a mention of that improve the documentation?

[ArcTanSusan]

It's better to be explicit with the installation instructions than assume that new contributors know how to do a thing.

I'm 👍 to mentioning autoenv.

[konklone]

@onceuponatimeforever does #50 help?