Workflow app for software

Ladies/Gents... Hi. Trying to get some input to a web based app for dealing with managing software apps/scripts. Basically, i'm envisioning a system where people register/signup, and then check in/out apps for development/testing/production... I need a way of dealing with users, assigning/accepting roles for the users, and to manage the flow of the "file" as it moves through the basic "development/testing/production" process. i'd like to have a database backend, combines with some kind of source/file reqpository... I've seen things like knowledgetree, owl, etc... but figured I'd get input from here. So, any thoughts to open source apps that you guys have actual experience using?? Thanks