I would like to build a custom image of ROOter. Info here:
Set up an OpenWRT build environment as described at the OpenWRT site.
Get the ROOter source files, e.g. from here, at the time of writing this (2018-02-06) the newest "packages" are GoldenOrb2017-12-15-4meg.zip (for 4 MiB images) and GoldenOrb2017-12-15-8meg.zip (for 8 MiB images).
Or get it from github.com/ROOterDairyman/Goldenorb, at the time of writing this (2018-02-06), it is the same except of some empty directories not present and unix style newlines (LF) instead of DOS style newlines (CR+LF).
Go to the directory where your OpenWRT sources are, and put the content of the file downloaded in the previous step under the supdirectory package/. You should end up with a directory package/rooter/ with several sub directories.
Build your OpenWRT as usual; under make menuconfig an entry ROOter ---> should show up.