I'm working on a application project which will be used by many customers, and they may need customization seperately. That is, assume that we sell our application to 1000 clients, we may need 1000 customizations (e.g. difference on handling connection, requests, etc.) on a single program. I think that we can create a git branch to customer by customer seperately, but 1000 branches on a single program? I don't think we can handle it properly. That's, not just what I wanted to. I want a "sustainable" solution. What should I do to manage that source code?
I know that there's a 'git flow' thing, but I just have no idea either it'll fit to this kind of situation.