Incomplete Seeding

Fixed the seeding bugs with much help from Michael.
there's a whole lot of ideas all in this one-liner. I'd be interested in seeing a verbose version that's more readable:
a line to define your array and sample from it, a line to explain/define the range you are putting that sample value into, and a line to then pick a random value from that range.
time_frames = [Time.now - 12.month, Time.now - 8.month, Time.now - 4.month]
date_range = (time_frames.sample .. Time.now)
rand(date_range)