... some level of higher hierarchy dependent on your client/app structure
ThisApp
dev
index.ascx
index.ascx.cs
test
index.ascx
index.ascx.cs
prod
index.ascx
index.ascx.cs
Where you add the files to the dev subtree. and then SHARE them down into the other folders. Developers to all their work in the dev subtree. When something is ready to promote to test, you pin the desired version in the test subtree and it gets deployed to the test webserver. When QA blesses it the pin is promoted in the prod subtree and deployed to the prod webserver.