No gap today. It simply traded that strong from just shortly after the bell.
Getting over 8.15 was crucial as that was a slightly downsloping resistance that had been in place for all of April. The next important test (and even more critical than today's move) is getting clear of ~8.60. If that happens then the stage is set of a minimum target of a little over 10.00.
That is JUST based on the chart and takes no news or other fundamental developments into account.