Web-software patch management

I'm developing a web-application that will be running on multiple webserveres.

I want to keep track of all updates/patches running on each installation. At the moment there is not a built-in function that auto updates or anything like that, so i will be updating these "installations" my self.

So the question is that is there any software(or web-app) or management tool that can help me manage these updates?

Example:

Customer 1 has updates: 1, 2, 3, 4, 5, 6

Customer 2 has updates: 1, 2, 3

Customer 3 has updates: 1, 2

Customer 4 has updates: 1, 2, 3, 4, 5

So when i apply update nr 4 to customer 2 i can just click it off.