A quick glance at the README.md indicates that you can input the hostname, port, etc. of your db at the command line, so it should work with AWS (your hostname would be something like blah.blah.us-east-1.rds.amazonaws.com).
Yes, it supports RDS and I want to support it as it's the one that I used most often. It's really basic right now but I will add some new metrics this month.
[1] https://www.opsdash.com/blog/postgresql-monitoring.html