[API] Warning: The .read and .rebuild APIs will stop working in the next Broccoli version
[API] Warning: Use broccoli-plugin instead: https://github.com/broccolijs/broccoli-plugin
[API] Warning: Plugin uses .read/.rebuild API: Flatiron
Probably just needs to be synced with DockYard's repo which has commit related to Broccoli v1.0.