Access specifications for subversion repositories is specified etc/subversion/svn_access_control file
Create/edit the file using following command
nano /etc/subversion/svn_access_control
Use following syntax to configure access permissions for repositories to group/members
[Repository:<Path>]
@groupname = r/rw
User = r
e.g.
[myproject:/]
@myproject-dev = rw
@myproject-support = r
jack = r
[myproject:/branches/support]
@myproject-support = rw
patrick = r
Above example configuration will grant read-write access to entire myproject repository to users belonging to group myproject-dev, while read-only access is granted to users belonging to group myproject-support and specific user jack.
Note that, group names are preceded by @.
Similarly, it will assign read-write access to support branch of myproject repository to all users belonging to myproject-support and read-only access to patrick.