If you want to use spaced repetition for studying openings, Listudy.org is the site for you :)
I created this because I like spaced repetition for learning, I have been using anki for studying for exams since years and I wanted to use the same concepts for learning chess. You can find openings to study here or create an account and upload your own studies.
I always appreciate feedback so if you have any please let me know!