1. A computer-implemented method comprising: creating, from a present version of a first artifact which is mutable, an artifact baseline corresponding to the present version of the first artifact; responsive to creating the artifact baseline, making immutable the present version of the first artifact and present versions of children artifacts of the present version of the first artifact which are mutable; and responsive to identifying a change to the present version of the first artifact, not saving the change in the present version of the artifact but, instead, automatically creating, by a processor, a new version of the first artifact, wherein the new version of the first artifact is mutable.