MovieRSS is a small app that let you ask Trakt.tv for your movie watchlist and then find the corresponding torrent using RARBG and expose them as an RSS feed.
docker run -p 8000:8000 -e TRAKT_KEY=xxx teambrookie/movierss
You can obtained one here: https://trakt.tv/oauth/applications
First of all, what you want is to set when you want the application to refetch the content of your watchlist and when to search for new torrents.
Personally I use IFTTT with a cron job.
First I call the endpoint responsable for refetching the content of the watchlist
http://localhost/refresh?action=movie&slug=trakt_username
Then I set a cron job for searching the corresponding torrent
http://localhost/refresh?action=torrent
And finally what really interest us is the /rss endpoint
http://localhost/rss?slug=xxx