Fastly on Pantheon Doc Update

[BrettCharbeneau]

Re: Fastly on Pantheon

Priority: Low/Medium/High (choose one, remove the other options)

Issue Description:

Guide is no where near complete. Pantheon support says to contact Fastly, Fastly support says Pantheon is responsible for maintaining documentation about the Pantheon environment.

Suggested Resolution

Keep the guides up to date!