Any object that can follow, watch, or be followed must subclass Node. See the User class on tv/timelines for an example. Just need to make Project do the same. Also, rename allura.model.timeline.Node
to allura.model.timeline.ActivityNode
and update the User and Project class definitions accordingly.
forge:tv/4387
Code review only. After QA, this should be merged back to forge:tv/timelines