If you need any further assurances that Warner Bros. Man of Steel is at least a major upgrade over 2005's Superman Returns, this news should ease your concerns. According to Deadline, the studio is wasting no time greenlighting the production of a sequel.
Studios don't usually move this quickly on sequels, bringing back the same director and screenwriter, unless they're hearing overwhelmingly positive feedback in screenings. The lack of a sequel to D.C. Comics' Green Lantern is proof of that. But let's not pretend this has anything to do with financing Zach Snyder's next artistic endeavor. With the Benjamins they stand to make, execs would rather get a follow-up in the works faster than a speeding bullet.