instantiate array/hash if it doesnt exist to instert a value. this is to avoid exceptions (done in a sexy way)

non-exception hash-array assignment

irb(main):001:0> a = {}
=> {}
irb(main):002:0> a[:b][:c] = 3
NoMethodError: undefined method `[]=' for nil:NilClass
  from (irb):2
	from /Users/dkelman/.rbenv/versions/1.9.3-p327/bin/irb:12:in `<main>'

=========================================
a = {}
(a[:b] ||= {})[:c] = 3
==============================
(hsh[line[:date]] ||=[]) << "blahblah"