doc: move production users to a standard ADOPTERS file

The details of production users fits better in the standard
ADOPTERS file as used by many other CNCF projects like
CoreDNS, containerd etc.
This commit is contained in:
Sahdev P. Zala 2019-10-17 18:36:28 -04:00
parent 51b1677d99
commit d73e04efd9