Stop failing at dating.

Well, maybe.

So:

1. Time#to_i returns seconds since the UNIX epoch.
2. new Date(number) takes milliseconds since the UNIX epoch.

No offset arithmetic is necessary.

To cleanse my hands of all of this annoying date stuff in the dashboard,
I'm dragging in moment.js.  It's not too big and it makes my intentions
clearer.  (So, if I've still goofed, at least someone can see what I
meant to do.)
To print out job status, we should amplify it first.
Record who started a job and in what channel.

Also move Job#set_depth into Job#register, and require that Job#register
record a whodunnit.
Record when a job finished.