Arc configuration

Summary:
[ Configuration ]

• Phabricator instance: DevCentral
• Repository: DOCKERWWW

[ Linters ]

• CSS
• JSON

Test Plan:

• jsonlint .arcconfig ; jsonlint .arcrc
• arc diff (tested with D63)
• arc lint css/app.css

Reviewers: dereckson

Differential Revision: http://devcentral.nasqueron.org/D64