Adding and removing users to a Subversion repository is quite a straightforward process, just do the following:

You’ll find a folder called “repos” in your filesystem which contains the different repositories you’ve created. You have to access the repository you need a new user’s access to (let’s call it myRepository) and add his/her entry to the “myRepository/conf/passwd” file under [users] in the format “newUsername = newPassword”, save the file and exit.

To do this, you can simply type “sudo gedit /repos/myRepository/conf/passwd” and add your entry, save the file and exit.