How to make the php script restart itself on error or lost connections?

Question

linux

Hello. Decided to try Ratchet php (socketo.me). But now the question is, everything is fine, the WS server is up and running, but how can I guarantee that if it crashes, it will restart? What tools can be used for this? Need to write your own daemon?
It is very important that the script with the WS server always works. And in the event of a crash or restart of the system, it started again.
PS Server on Debian 8
Thank you.