I am new to Rclone and quite like it!
I am not a lazy guy, just not smart enough to figure out the right keywords to search for and find the answers to my problem here! 
But I do see a lot of people asking "auto mount on startup" during my search, especially with docker, so I'd like to share my workaround, not sure if anyone else did it before though.
Basically the idea is " One container, one remote", the container will run from a "new" image based on rclone/rclone.
I added an SH file as entrypoint for this new image, it will find out if the config file exists, then run "rclone config" if False, and "rclone mount....." if True. the SH file can be mounted from the host so that you can copy, edit and create a new container for a new remote. So far it is working fine on my server (Linux), I tried rebooting, and restarting the container again and again, and everything seems great!
I am not sure if it's allowed to do like this, (as I don't use the rclone/rclone directly but build a new one based on it). If allowed, and anyone is interested, I'll be glad to post the files (SH file, dockerfile, as well as the new image) and discuss.
Thanks for reading 
If this is a repeated topic, or it does any offense, feel free to delete it.