>> Request
=> Request(id: integer, inserts: integer_array, updates: integer_array)
>> r = Request.new
=> #<Request id: nil, inserts: [], updates: []>
>> # These array columns have an empty array set as default!
>> r.inserts
=> []
>> # This doesn't work
>> r.inserts << 7
=> [7]
>> r.inserts
=> []
>> # But this does
>> r.inserts += [7]
=> [7]
>> r.inserts
=> [7]
>> # And now, this too
>> r.inserts << 9
=> [7, 9]
>> r.inserts
=> [7, 9]
