Update docker readme
Update docker readme

Change-Id: I3cb832133ddb993e469991bfedbca623563818b0
Reviewed-on: https://gerrit.instructure.com/101024
Tested-by: Jenkins
Reviewed-by: Shahbaz Javeed <6692d7be3fa215e5483a121d6fb314def6049877@instructure.com>
Product-Review: Neil Gupta <cc4fec8a34766005dd45d48be045c08d736c11ed@instructure.com>
QA-Review: Neil Gupta <cc4fec8a34766005dd45d48be045c08d736c11ed@instructure.com>

SwinburneOnline/canvas-lms,matematikk-mooc/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,matematikk-mooc/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,matematikk-mooc/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,matematikk-mooc/canvas-lms,SwinburneOnline/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms