FastVersion
FastVersion is a Qgis plugin for data versioning in a Postgis database
...The system uses algorithms and data structures so that information is not duplicated each time a version is created.
We recommend downloading it from the Qgis app.
Plugins->Manage and Install Plugins->Settings->Show also experimental plugins
Plugins->Manage and Install Plugins->Search FastVersion
If downloaded from sourceforge, it must be unzipped in \.qgis2\python\plugins