I and my companions often work with freelancers on the creation of small sites. After a period of development followed by a period of testing, and then to move on already "fighting" server. But even after the full launch of the site sometimes bugs are found and/or the client wants some new feature. I would like to organize a web interface where the customer could see how much interest we have completed the requested feature and/or could make the bug in the bug list for us to fix. What CMS fit in?