Show history of assignments, pickups, etc. for each ride

[smarbin]

Trying to troubleshoot what happened with rider, driver was assigned, then not, if it was cancelled by one of the admins or support team, or cancelled by the driver.... would be helpful to have that running history on the ride details page.

[john]

Added a dupe by accident (#1128), but I'm going to keep that open too, since it's a little different--the gem just gives you a pretty vanilla way to see object history, as opposed to properly integrating that with the dispatch app views.