I suggest to run this on a management server which poll the config and save. You can offload these activities from ASA and let it focus on security.
I am sure most of the network management have autobackup servers our of the box as dedicated services.
If you still looking to run on the box as suggested on other post EEM is the option
Depending on the ASA version you are running, you could set up an EEM script to send the output of more system:running-config to an ftp / tftp server.
https://www.cisco.com/c/en/us/support/docs/security/adaptive-security-appliance-asa-software/117883-config-eem-00.html